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ncer in Charge of Welding Instruction, 
Ordnance Department, U.S. Army. 





Copyright, 1919 


Copyrighted in Great Britain 






(1) THE oxy-acetylene method of welding and cutting 
metals has of late been receiving considerable attention. 
Its tremendous power of creating, repairing and destroying 
the work of man has been but recently recognized in its 
broadest sense, and the demand for operators, skilled in 
the manipulation of this apparatus, which always has been 
far in excess of the supply, now knows no limit. Many 
authorities have set forth their views and theories upon 
this subject, in America and also in foreign countries. These 
have been published from time to time in many of the leading 
periodicals and magazines, as well as in book form. It seems 
the purpose of most of these works has been to advance 
the operators who already have a smattering knowledge of 
this art, or to present to the purchaser of apparatus a set 
of operating instructions. 

(2) It is singular indeed that a school manual, devoted 
exclusively to the instruction of the beginner, which will 
serve as an aid to the instructor as well as to the student, 
has not yet been put forth. It cannot be said that there 
is not a demand for such. Recently there seems to have 
been a mushroom growth of welding classes. The majority 
of the vocational schools, colleges, night schools, and auto- 
mobile schools have all entered the instruction in oxy- 
acetylene welding on their rolls and each is attempting to 
instruct in an entirely different manner from the other. 



There can be no question as to the expediency of affording 
the educational institutions a systematic as well as a stand- 
ardized method of instructing. But the books and articles 
of the nature mentioned are not suited to this purpose, 
and were not designed for it. A school-book is wanted; 
something to be used in the classroom, to be employed as 
a reference in the shop practice, to be studied for what it 
contains, and to indicate further lines of research, where 
such are required. 

(3) To meet this demand, the present" Manual" has 
been written to serve the instructor as well as the student. 
In its preparation many books, both well-known and 
obscure, have been examined and the methods of shop 
instruction have been carefully studied by the author. 

(4) It has been found that regardless of how fast the 
ground may be covered in the lecture room, the average 
student's power of assimilation is limited and considerable 
time has been spent in determining this ratio and applying 
it between the lecture subjects and shop work. 

(5) It must be remembered that while the chapters com- 
prising the theoretical part of this welding manual follow 
in the order given, the actual shop practice, as previously 
mentioned, is the most important. 

(6) Kindly aid has been received from many sources. 
Granjon & Rosemberg, Kautney, M. Keith Dunham, S. W. 
Miller, Henry Cave, C. J. Nyquist, P. F. Willis, Ben K. 
Smith, and others have embodied in their writings many 
excellent ideas, which have assisted the author in bringing 
out certain points advantageously. The following manu- 
facturers are to be given credit for many of the illustrations: 

The Oxweld Acetylene Co., Newark, N. J. 

The United States Welding Co., Minneapolis, Minn. 

The Bastian Blessing Co., Chicago, 111. 


The Linde Air Products Co., New York City. 

The General Welding & Equipment Co., Boston, Mass. 

The Messer Manufacturing Co., Philadelphia, Pa. 

The Alexander Milburn Co., Baltimore, Maryland. 

The Torchweld Equipment Co., Chicago, I1L> 

The Davis-Bournonville Co., Jersey City, N. J. 

The K. G. Welding Co., New York City. 

The Chicago Eye Shield Co., Chicago, 111. 

The Commercial Acetylene Supply Co., New York City. 

The Welding Engineer, Chicago, 111. 

The Journal of Acetylene Welding, Chicago, 111. 

NOTE. Lieut. Campbell offers his services without charge to anyone 
interested in this method of welding and may be addressed care of JOHN- 
WILEY & SONS, INC., Publishers, 432 Fourth Avenue, New York City. 


THE Wiley Engineering Series will embrace books devoted 
to single subjects. The object of the Series is to place in the 
hands of the reader all the essential information regarding 
the particular subject in which he may be interested. 
Extraneous topics are excluded, and the contents of each 
book are confined to the field indicated by its title. 

It has been considered advisable to make these books 
manuals of practice, rather than theoretical discussions of the 
subjects treated. The theory is fully discussed in text-books, 
hence the engineer who has previously mastered it there, is, 
as a rule, more interested in the practice. The Wiley En- 
gineering Series therefore will present the most approved 
practice, with only such theoretical discussion as may be 
necessary to elucidate such practice. 


























INDEX ' . . 167 


Oxy-Acetylene Welding Manual 


(i) WHEN choosing a life vocation, one generally views 
the possibilities it has to offer and delves deeply into these, 
previous to making a decision. It is therefore thought 
advisable at this time to present the student with an idea 
of what is meant by oxy-acetylene welding and cutting; 
how it is applied; the possibilities and advantages attached 
to such an art. 

(2) Acetylene gas, when burned with a proper portion 
of oxygen gas, produces an extremely hot flame, in fact, 
the hottest flame known. Its temperature is over 6000 
degrees Fahrenheit. With this flame it is possible to bring 
any of the so-called commercial metals, namely: cast iron, 
steel, copper, and aluminum, to a molten state and cause 
a fusion of two pieces of like metals in such a manner that 
the point of fusion will very closely approach the strength 
of the metal fused. If more metal of like nature is added, 
the union is made even stronger than the original. This 
method is called oxy-acetylene welding and differs from 
what the average layman considers welding in the black- 
smith's forge, insomuch that there is no blow struck to 
assist fusion in this process. And while the forge method 
is limited to wrought iron and steel which is detachable 



and of restricted size and shape, the oxy-acetylene process 
has, practically speaking, no such limitations. d 

(3) Manufacturers in the metal- working world were 
very slow to grasp the real significance of this important 
process, until the operators began demonstrating some of 
its possibilities. At the present time, however, there is 
hardly a metal barrel or tank 

manufacturer who has not 
discarded the old method of 
producing costly leaky, riv- 
eted drums and containers, 
for this modern fusing proc- 
ess. The manufacturers of 
fire-proof doors and windows, 
cooking utensils, seamless pipe 
and tubing, office furniture 
and what not, are now vir- 
tually dependent upon the 
welding torch at every turn. 

(4) As a repairing agent, 
the welding torch has no 
rival. Whether it is a cast- 
ing of iron, steel, brass, or " "^r^ 

aluminum that has broken ; (Courtesy of the Oxwela Acetylene Co.) 

a boiler or tank that has FlG - 2 ~ In Enameled Products for the 

Kitchen the Weld is Fast Replacing 

worn away in spots, or an -,-.... D . , c v 

J ' the Riveting, Brazing, and Soldering 

error on the part of en- of the Light Sheet Metal Seams, 
gineer, foundryman or ma- 
chinist, the part can generally be reclaimed and made 
stronger than originally. To-day practically no manufac- 
turing concern that is dependent upon metallic machinery 
could think of being deprived of its oxy-acetylene apparatus, 
once having learned its worth. In the not far distant past, 
were a gear or some casting to break, it probably meant closing 


down the entire plant until a new part could be obtained, 
which, whether the source of supply were near or at a long 
distance, would mean costly delay. With oxy-acetylene 
equipment and an efficient operator on hand, almost every 
emergency is provided for. 

(5) If an automobile owner breaks a frame, he does not 
consider replacing it with a new one, as the labor alone for 

(Courtesy of the Oxweld Acetylene Co.) 
FIG. 3. Welding Broken Frame of 5-ton Automobile Truck. 

stripping his machine and setting it up again, not to men- 
tion the cost of the new frame and the time required for 
this operation, is prohibitive. Rather, he has his car taken 
to the nearest welder or his portable apparatus to the car 
and the job is completed within thirty or forty minutes, 
with the frame at the point of the break made stronger 
than ever. Locomotive frames are handled in much the 


same manner, only more time is required and perhaps extra 
operators, but the important point to be brought out is 
the fact that on many jobs no dismantling is required and 
the repair is permanently and quickly executed. 

(6) An interesting example of the true worth of welding 
was brought to the attention of the public when the United 

FIG. 4. Staff of Instructors at the Ordnance Welding School, U. S. A. 

States entered the European War, and all the interned 
German vessels, which had been greatly damaged by the 
orders of their commanding officers, were restored to working 
condition with the oxy-acetylene and electric welding process. 
This was considered impossible by many engineers not fa- 
miliar with the process, insomuch as they looked upon oxy- 
acetylene welding as applicable only to small parts and 


here some of the sections which had been blown or struck 
out of the cast cylinders, etc., weighed many hundreds of 
pounds. In many instances the ribs of these same vessels 
were cut most of their depth, but these were restored to 
working order in a remarkably short time and the results 
were more convincing than any words. 

(7) Cutting with the oxy-acetylene process is just the 
opposite from that of welding. The latter might be con- 
sidered constructive and the former destructive. In the 
case of welding, two parts are brought to a molten condition 
along the line to be joined and both fused together. Whereas 
in cutting, one piece of metal, when brought to a red 
heat, is cut in two by an oxidizing flame. Cutting has not 
the wide scope that welding has, for it can only be applied 
successfully at the present day to wrought iron, rolled and 
cast steel. While it is limited in its scope, the speed of 
this process in severing large masses of metal is very spec- 
tacular and appeals forcibly to the observer. 

(8) Probably the world's first awakening to the real 
meaning of oxy-acetylene cutting came when the U. S. 
battleship " Maine," was being taken from Havana Harbor. 
All the heavy armor plate and seemingly immovable wreck- 
age was cut into small sections which could be handled 
easily. This was all accomplished with the cutting torch, 
which seems to eat its way through metal with the same 
ease that a hot knife goes through butter. 

(9) Before and since the time of the " Maine," the cutting 
torch has been accomplishing wonderful feats. In every 
scrap yard, old boilers and the like are being cut into fur- 
nace size; speeding up the production in answer to the 
world's cry for more metal. The wreckage on railroads and 
buildings using steel reinforcements is being cleared in 
hours, with the aid of the cutting torch, where it required 
days by other methods. Most of the fire departments in 


the larger cities now carry the cutting torch as part df their 
equipment, and to it has been credited the saving of many 
lives, by its timely cutting away of steel doors, bars or barriers 
which prevented escape. Much of the plate in this country's 

(Courtesy of the Oxweld Acetylene Co.) 
FIG. 5. Fireman Cutting |-inch Steel Fire Door with Portable Apparatus. 

shipbuilding yards is being cut to size right on the job, and 
the function of this torch in cutting off risers measuring 
from one to thirty-six inches in diameter in the foundry 
seems only to be of secondary importance in comparison with 


some of its other uses. In order to transport some of tf 
largest inland lake boats which were much too long to pai 
through the locks, to the sea, they were cut in parts, tran 
ported, and later welded together and placed in service. 

(10) It is not only possible to keep a cutting torch bun 
ing under water, but it can also be made to cut. Coi 
tracting companies are cutting off their piling under wat< 
and it has been known that in European ports cutting hi 

(Courtesy of Itie Acetylene Journal Publishing Co.) 

FIG. 6. Welders of the Signal Corps, U. S. Army, in Action. 

been successfully accomplished at a depth of thirty feet 
A special torch is employed by submarines to cut nets unde 

(n) In reviewing the oxy-acetylene welding and cuttinj 
process, we find that its growth is one of the most remarkabl 
the world has ever witnessed. About 1907 saw its industria 
birth and since that time it has advanced by leaps am 
bounds, rivaling the automobile industry in its progress 



despite the opposition and criticism levied at it by workers 
of other trades and its careless and unskilled manipulation. 
(12) It is quite impossible to present anything like a 

(Courtesy of the Acetylene Journal Publishing Co.) 

FIG. 6a. Welders of the Signal Corps, U. S. Army, in Action. 

complete list of the applications of this process, but a few 
of its general uses are here enumerated: 

(A) Airplane Construction. Welding of frames, sockets, 
water and gasoline tanks, water jackets and valve cages to 


cylinders, intake and exhaust manifolds and connections, 
spark plug thimbles and the repair of aluminum crank 
cases, etc. 

(B) Automobile Manufacture. Welding of steel and alu- 
minum bodies, transmission and rear axle housings, crank- 
shafts, cylinders, gears, manifolds, pinions, crank cases, valves, 

(Courtesy of the Oxweld Acetylene Co ) 

FIG. 7. Welding a 2 -foot Length of New Shafting on the End of a Motor 
Shaft 2 Inches in Diameter. 

rims, mufflers, frames, fenders, wind-shield tubings, and 
uprights, etc. 

(C) Boiler Shops. Welding and building up worn spots 
around hand-hold plates, repairing cracks and checked 
portions of fire boxes, retipping flues, connections, etc. 

(D) Brass and Copper. Welding kettles, vats, tanks, 



stills, floats, cooking utensils, manifolds, water jackets, 
electrical and chemical wares, etc. 

(E) Commercial Welding. Reclamation service on all 
kinds of metals, quick and permanent repairs on all broken 
parts of machinery. 

(F) Electric Railway. Welding air receivers on air-brake 
systems, building up shafts, bonding the rails, motor housings, 

(Courtesy of the Torchweld Equipment Co.) 

FIG. 8. This is a Steel Tank, Made of f-inch Plate, which Measures 30 Feet 
Long and 8 Feet in Diameter, Fused into One Piece by the Welding Torch. 

worn boxes, reclaiming gears and broken trucks, steel trolley 
wires, etc. 

(G) Forge Shop. Welding complicated parts which can 
not be conveniently handled in the forge. 

(H) Foundries. Welding up blowholes, porous spots, and 
reclaiming castings in general. The cutting off of risers, 
gates, and heads on steel castings. 



(I) Lead Burning. Lead pipe joints, storage battery 
connections and repairs, lead linings in vats, etc. 

(Courtesy of Ben K. Smith, U. S. Welding Co.} 
FIG. 9. Locomotive Cylinder to be Welded in Place. 

(J) Lumber Mills. Building up worn shafts, repairing 
gears, chains, and broken parts. 

(K) Machine Shops. Rectifying errors on part of ma- 
chinists and engineers. A "putting-on" tool in every respect. 

(L) Manufacturers. Welding spouts and handles on 



cooking utensils, fire-proof doors arid window sashes, office 
files and furniture, chains, etc. 

(M) Mines. Repairing pipe lines, boilers, broken shafts, 
gears, and building up worn parts on dippers, etc. The 
cutting torch is used for clearing away wreckage in case of 

(N) Pipe Work. Welding of water, gas, and oil, steam 

(Courtesy of the Oxweld Acetylene Co.) 

FIG. io. Steel Roll Top Desk all Joints and Seams Welded. An Excellent 
Example of High-grade Welded Metal Furniture. 

and air lines. High-pressure refrigeration systems are cut 
and welded in place. 

(0) Plate Welding. Tanks for oil, steam driers, digesters, 
vats, chemical receivers, generators, etc. 

(P) Power Plants. Welding of steam, air, and water-lines, 
of pump castings, cylinders, pistons, worn or broken parts, etc. 

(Q) Railroad Work. Reclaiming bolsters, couplings, slot- 


ting forged engine rods, building metal cars, repairing fire- 
boxes, patching and replacing side sheets, flue welding, build- 
ing up frogs and crossings, cutting off rails, mud rings, weld- 
ing cracked cylinders, cross-heads, steam-chests, building 

(Courtesy of the Oxweld Acetylene Co.) 
FIG. ii. Office Chair. Welded at all Joints. 

up worn spots on wheels, rims and pins, welding spokes 
and locomotive frames, etc. 

(R) Rolling Mills. Fabricating " open-hearth," water 
jacket doors, cutting up "lost heats," scrap plates and bar 
stock billets. General repairs of furnace equipment, hot 
beds, rolls, gears, engines, plates, etc. 


(S) Sheet Metal Manufacture of tubing, oil-storage 
barrels, metallic furniture, range boilers, etc. 

(T) Shipyards. Cutting off plates and irregular shapes 
of steel, channels, special sections. Building up of worn 
shocks, building and patching hulls, stringers and the reclama- 
tion of propellers, posts and broken parts of machinery, etc. 

(U) Structural Steel Cutting holes for rivets, gussets and 
splice plates, and wrecking. Welding up misdrilled holes 

(Courtesy of the British Oxygen Co.) 
FIG. 12. Cutting Armor Plate by the Oxy-acetylene Process. 

and machinist's errors. Cutting channels, I beams, and 
other shapes for coping, splicing and fitting rails, welding 
reinforcing rods for concrete work of any desired length 
and structural parts where bolting and riveting is difficult 
or impossible. 

(V) Scrap Yards. Cutting up scrap boilers, tanks and 
other large work to mill size, wrecking structural buildings, 
and reducing to small size, reservoirs, tanks and boilers, 



which are housed in buildings to remove them without 
damage to the structures. 

(W) Tractor Industry. Cutting and welding frames, 
track and wheel guards, water, gasoline, and oil tanks; 


(Courtesy of the Davis- Bournonville Co.) 

FIG. 13. Here is Illustrated an Oxy-acetylene Machine for Cutting Holes 
in the Web of Rails, or in Structural Iron, of not more than f Inch in 
Thickness. It can be Quickly Attached and Accurately Adjusted to 
Pierce through the Iron Instantly, without any Previous Drilling, and 
it will Cut Smooth Round Holes, from \ to 2 Inches in Diameter in from 
30 to 60 Seconds. It is Particularly Adapted for Railroad Work, and 
Enlarging or Cutting Holes in Building and Bridge Work. 

welding up of blowholes, porous spots and misdrilled holes 
in castings of all kinds. 

(13) The foregoing, as previously stated, is but a partial 
list of some of the applications of the oxy-acetylene welding 
and cutting process to various industries. What has the 


future In store for it? Almost daily, some new application 
is found for it and at the present time experiments are under 
way in boiler construction, the results of which are not dif- 
ficult to foresee. Giant hulls of seagoing vessels are being 
fused together by welding and the limits of this wonderful 
process which is now practically in its infancy are difficult 
to forecast. 

(14) During the World War many manufacturers of 
non-essentials shut down and others turned their entire 
production over to the government, changing their machinery 
and in most instances their entire plant. What, then, are 
those who are operating machines and apparatus, produced 
by these firms before the war, going to do for replacements? 
There is but one answer, have their broken or worn out 
parts welded. 

(15) Oxy-acetylene operators have always numbered far 
less than the demand, a point which was clearly brought 
out by the government when its immense Army and Navy 
were being formed. There were so few men familiar with 
the oxy-acetylene process that it at once took measures to 
establish its own schools where men could be trained, a 
thing that the commercial world had been THINKING of 
doing for some years. As the demand for operators con- 
tinues to increase, it behooves a man, even though he 
is not a metal worker, to think and apply himself, in order 
that he may "carry on," to the best advantage when oppor- 
tunity knocks. 

(16) The methods of instruction herein set forth are 
very simple and while differing in many respects from those 
used by the trade, have been most successfully employed 
in producing efficient operators. Certain principles are in- 
stilled in the beginner and some of the exceptions which are 
of minor importance are overlooked to avoid confusion. 
Criticism is expected from those who have never engaged 


in instruction of this kind on a large scale. There are many 
differences to be expected on account of this very fact, for 
there are few who have gone further than the instruction 
of very small classes where individual attention may be 

(17) All history of the process, gas manufacture and the 
like have been omitted in order to give greater detail to 
the actual shop practice and to have the operator become 
familiar with his apparatus and thereby operate it with all 
due respect and intelligence. 

(18) Oxy-acetylene welding cannot be learned by watching 
others work, although observation may at times assist the 
beginner. Actual torch practice, brain work and a power 
of "I will," produce the most efficient operators. For those 
who earnestly apply themselves to the instructions which 
follow, there is every reason to believe that success will be 


(19) WELDING apparatus in general consists of two regu- 
lators equipped with pressure gauges, two lengths of hose, 
and a welding torch. The regulators are attached to cyl- 
inders of acetylene and oxygen and are used to reduce and 
maintain a uniform pressure of these gases for use at the 
torch. The gases at reduced pressure are conveyed to the 
torch by the hoses. The regulators should each have a 
high-pressure gauge to indicate the contents of the cylinder, 
and also a line or working-pressure gauge to show the gas 
pressure on each hose. When the gases reach the torch they 
are there mixed and combustion takes place at the welding 
tip, which is fitted to the torch. Such an apparatus is called 
portable, on account of its movability. There are other 
equipments wherein one or both of the gases are generated, 
but these will not be discussed here. 

(20) For convenience oxy-acetylene welding apparatus 
may be divided into three classes, depending upon the prin- 
ciples used in securing the fuel gas or acetylene for the flame. 
Low-pressure, medium-pressure and high-pressure apparatus 
generally use about the same pressure of oxygen and it will 
be called a constant. The acetylene gas is a variable and 
in the low-pressure type only enough pressure is required 
to overcome the friction of the line until it reaches the oxy- 
gen injector, located in the torch, which acts as a syphon, 
drawing the acetylene gas to the point of ignition. In a 
medium-pressure type about three-fourths as much pressure 




is required on the acetylene line as on the oxygen. This 
type is apt to verge on the injector type, as it depends to 
some extent upon the oxygen under pressure carrying acety- 

FIG. 14. A Portable Welding Unit. 

lene gas to the point of ignition. In the high-pressure type 
equal pressure on each line is used. To further make this 
classification clear, a certain sized tip using, perhaps, 12 


pounds of oxygen pressure can be used as an example. In 
a low-pressure type perhaps 2 pounds pressure or less will 
be needed on the acetylene line. On the medium-pressure 
approximately 9 pounds will be required, while on the 
high-pressure an equal amount, or 12 pounds will be needed. 
(21) The mixing chambers for the gases may be located 
in the head; in the middle of the torch, or in the handle. 
By mixing chambers reference is made to that portion of the 
torch where the two gases are brought together and mixed. 
As can be seen with three different types of welding torches 


FIG. 15. Location of Mixing Chambers in Welding Torches. 

(i) Shows gases mixing in the handle. (2) Has the mixing chamber in the middle of the 
torch. (3) Illustrates how the gases are kept separate until the head of the torch is reached. 
Ox. represents oxygen gas; Ac. acetylene gas; and m mixing chamber. 

and three different locations for the mixing of the gases, 
the manufacturers can find a large range for producing 
oxy-acetylene apparatus. Some undoubtedly will fill cer- 
tain requirements better than others. Much, too,' will de- 
pend upon the ability of the operator in handling a torch. 
(22) Flashbacks are caused by the improper mixture of 
the gases, which increases the rate of flame propagation to 
such an extent that the flame will flash back to the mixing 
chamber. Acetylene in a pure state will burn very much 
slower than when mixed with equal parts of oxygen. When 


more oxygen is introduced the flame propagation is much 
greater, so that when an excess of oxygen is used, there 
is bound to be considerable trouble from backflashing. When 
sufficient acetylene is introduced to the mixing chamber, 
there is absolutely no chance for this lean mixture to occur. 
If the flame flashes back to the mixing chamber, both gases 
should be closed off immediately, at the torch, the oxygen 
first, and then the acetylene gas. 

(23) In some torches the heating of the mixing chamber 
will cause a flashback and with these it is necessary to shut 
off the acetylene and leave the oxygen valvs just cracked 
and immerse the torch head in water, dipping it slowly, 
so as not to cause too great a strain. The oxygen will bubble 
out and prevent the water backing up in the tip. If the 
flashback deposits enough soot on the inside of the tip and 
the head to impair the working quality of the torch, the 
soot should be removed by using a soft wire, preferably of 
copper, or some other material which will not mar the tip. 

(24) It is interesting to note the action of a regulator, 
used to reduce the cylinder pressure on both gases. The 
gas from the cy Under, at high pressure, comes directly into 
the body of the regulator or chamber (4), Fig. 16, through 
a fine nozzle (B). A seat of gallilith, casenite, or fiber 
(C), attached to an arm (D), presses against this nozzle. 
Arm (D), in turn, is attached to a very sensitive diaphragm 
(E) and is moved every time there is a pressure exerted on 
the latter. The movement of this diaphragm is controlled 
by a handle or a screw, with a " cross-bar" attached to 
its end as is shown at (F). This screw bears upon the dia- 
phragm through the medium of the springs (G). As this 
screw is forced inward the springs force the diaphragm in, 
and thereby move the seat away from the nozzle of the 
regulator. The gas, entering under high pressure, exerts 
an equal force on all parts of the chamber and the diaphragm 



receives its share. Now the, chamber walls are made of 
a solid material, usually a bronze or brass, and cannot be 
changed, but this diaphragm can be moved and as this 
pressure is increased, the diaphragm is forced out and the 
nozzle (B) is automatically closed by having the seat (C) 
brought in contact with it. When gas is drawn off through 
the line (H), the pressure within the chamber will naturally 

FIG. 1 6. Cross-section of Regulator. 

A, chamber; B, nozzle; C, seat; D, seat arm; E, diaphragm; F, cross-bar, or adjusting 
screw; C, diaphragm springs; H, gas outlet; /, gas inlet. 

drop and as it does so, the springs will force the diaphragm 
inward, permitting a replacement of the gas drawn off. 
Although not noticeable, there is a continual movement of 
this diaphragm whenever the gas is being used. It can be 
readily seen that the amount of pressure within the regulator 
can be accurately set by the tension of the spring against 
the diaphragm which is controlled by the screw carrying 
the "cross-bar." 


(25) There are two types of regulators manufactured for 
the reduction of gases under high pressure, depending upon 
the nature of work to be done. The high-pressure regulator 
is employed for heavy work where a great deal of gas is 
used and the regulator must pass it without much effort, 
to prevent its freezing. This type of regulator is used on 
cutting or on large welding work. It differs from the low- 
pressure or ordinary type in four distinct features. Generally 
it contains a much heavier diaphragm which is smaller in 
diameter, making it stiffer in every respect. The tension 
springs which act upon this diaphragm are much heavier. 
The nozzle which presses against the seat is much larger, 
to permit the passage of a greater amount of gas. Then, too, 
a larger working pressure gauge must be used, in order to 
read this high pressure. In the welding of metals, especially 
in steel, the adjustment of the flame is a very important 
matter, and absolutely dependable regulation must be had. 
This is not possible with a high-pressure regulator and is 
not intended to be so. The larger the diaphragm, the more 
sensitive the regulator, and this point should be borne in 
mind, and no small welding work attempted with the high- 
pressure regulator. The reverse form of reasoning may 
be applied to low-pressure regulators which have been used 
in cutting. They are very likely to be strained and satis- 
factory results cannot be expected, for they are not made 
for that purpose. Acetylene regulators are constructed much 
more sensitively than the oxygen regulators, to take care 
of the lower pressure of gas and in a sense might be 'called 
weaker, insomuch that the larger nozzle which passes the 
gas is closed or regulated by springs which are not nearly 
as strong as in the oxygen regulator. For this reason acetylene 
regulators cannot be interchanged with oxygen regulators 
for they will not stand the pressure demanded in the first 
place, and in the second place, were a small quantity of 


acetylene gas left in the regulator and oxygen introduced, 
an inflammable mixture would be formed which is not ad- 
visable to have present, on account of its explosiveness. 
In many instances oxygen regulators are put out with the 
copper diaphragms, whereas another metal must be used 
on the acetylene regulators, because acetylene gas attacks 
copper and usually a German silver or rubber diaphragm 
is used. On account of the lower pressures used in charging 
the acetylene cylinders, lower pressure gauges are used 
than on oxygen regulators. 

(26) All tension should be removed from the diaphragm 
springs by screwing out on the " cross-bar" (that is, to the 
left), before admitting gas under pressure to the regulator 
to avoid abusing the seat. If a matter of 1800 pounds 
pressure were admitted suddenly into any regulator that 
had the seat removed from the nozzle, there would be a 
sudden exertion upon the diaphragm, which would draw the 
regulator seat up very violently against the nozzle, and if 
it did not crack the seat it would undoubtedly groove it 
to such an extent that it would leak and a trouble known 
as "creeping regulator" would result. If this occurs, good 
work cannot be expected because the flame will not remain 
steady, and it is therefore necessary to take steps to rectify 
this abuse. If there is a welding company available, the 
regulator should be sent to it for repairs, but if the operator 
is in an isolated district when this occurs, and must have 
some means of continuing work, it will be possible for him 
to remove the seat by unscrewing the back of the regulator. 
If the seat has become grooved, and he thinks that this 
is the trouble, many times the seat can be turned over and 
the machined surface on the other side used. If the seat 
is cracked, however, about the quickest way of making an 
emergency repair is to turn out a new seat from hard rubber 
ir fiber on a lathe. 


(27) In acetylene cylinders an absorbent called acetone 
is generally used, which gives up the gas as required. A 
full cylinder can be used for some time without any noticeable 
difference in the gauge reading, and then, as it nears the 
empty point, the gauge reading will drop very perceptibly. 
It is therefore impossible to depend upon a high-pressure 
acetylene gauge as an index to the contents of the cylinder. 
The only method known to correctly check the amount of 
acetylene gas on hand is to weigh the cylinder. There are 
14^ cubic feet of acetylene gas to the pound, and when the 
net weight of the cylinder is given the contents can readily 
be figured. A tag bearing the net weight or figures which 
will permit its computation is generally found attached to 
each acetylene cylinder. In the case of oxygen cylinders, 
there being no absorbent used, the contents of the cylinder 
is indicated on the high-pressure gauge. On the latest 
type gauge the contents will be shown by cubic feet, by 
pounds pressure and by atmospheric pressure, to facilitate 
the computation of costs by the operator. 

(28) Occasionally a needle valve on a torch will begin 
to leak and it will be found necessary to grind it. Realizing 
that oil and grease are not to be used where oxygen is in 
evidence, the question is often brought up as to the proper 
lubricant to be used in doing this kind of work. Glycerine 
is used by most manufacturers, together with powdered 
glass or flour emery. In doing work of this kind the finished 
job is thoroughly washed with ether. Occasionally when 
piping oxygen lines through the shop, a screwed coupling 
will leak and there is a temptation to calk the same with 
white lead, but this should never be done, rather use lead 
oxide mixed with the glycerine for this purpose as it forms 
a paste which sets very rapidly and forms a hard, tough 


(29) IN oxy-acetylene welding there are two gases used, 
as the name would indicate, namely, oxygen and acetylene. 
The first is used to intensify the flame and can in nowise 
be likened to the inflammable nature of the second. There 
is a great deal of oxygen present in the air we breathe. It 
is an odorless, tasteless, and colorless gas, as most of us are 
aware. In the commercial world oxygen is manufactured 
by the decomposition of water into its elements, oxygen 
and hydrogen, by the electrolytic process or is taken from 
the air by a reduction process and is stored in steel-drawn 
cylinders. These cylinders are drawn out of one piece of 
steel and are of considerable thickness throughout, having 
absolutely no seams, welded or otherwise. There is no filler 
nor absorbent used on the inside of these cylinders, as pure 
oxygen under pressure is not considered dangerous. The 
standardized sized oxygen cylinder is one which contains 
200 cubic feet of gas fully charged. Oxygen is compressed 
in these cylinders at a pressure of 1800 pounds, at normal 
temperature, and this pressure does not vary to any great 
extent with change in temperature (as shown by table on 
page 29). There is attached to the tip of the steel cylinder, 
or "bottle," as some workers call it, a double seating valve 
which has one seat operate when the cylinder is closed, 
and the other when the cylinder is wide open. A regulator 
is attached to this valve when working. 




FIG. 17. Sectional View of 
Oxygen Cylinder without 

(Courtesy oj the Linde Air Products Co.) 

FIG. 1 8. A Standard 2oo-foot Oxygen 



(30) Acetylene is the fuel gas, and is one of the greatest 
containers of heat known. Burning in a free state, its 
carbon content is so rich that complete combustion is im- 



Lb. Per 


Lb. Per 


Lb. Per 


Lb. Per 















7 6 



















































J 59 6 









































































































































FIG. 19. 

possible, and stringy black particles will be noticed floating 
through the air. In order to fully combust this gas, oxygen 
is introduced under pressure and a temperature of over 



6000 degrees Fahrenheit is obtained. (Acetylene contains 
about five times as many B. T. U.'s (British Thermal Units) 
as hydrogen.) This gas, unlike oxygen, becomes very dan- 
gerous when in a free state it is subjected to an excessive 

FIG. 20. A Generator for Producing Acetylene under Pressure. 

pressure. The slightest jar may cause its disintegration 
and a violent explosion follows. On account of this 
danger, acetylene is not stored in a free state; neither is it 
subjected to very high pressures. Its cylinders are put 


out by various manufacturers to comply with the laws and 
regulations of the Interstate Commerce Commission. Some 
of these cylinders have been welded, but the most modern 
method is to make them of one piece of drawn steel They 
are then filled with an absorbent of some kind to take up 
the gas and prevent any portion of it being left in a free state. 
Acetone is the popular absorbent, and is a liquid capable 
of absorbing twenty-five times its own volume of acetylene 
gas at normal pressure. The filling material varies with each 
of the manufacturers, but charcoal, asbestos and mineral wool 
are in very common use. Acetylene is obtained from calcium 
carbide brought in contact with water, or vice versa, and 
is compressed and then stored in the cylinders at a pressure 
varying from 150 to 250 pounds. When fully charged 
this pressure will vary almost directly with any change 
of temperature. Acetylene cylinders for welding are avail- 
able in 100, 200, 225, and 300 cubic foot sizes. 

(31) In setting up apparatus for the first time, the regu- 
lator containing the 3ooo-pound gauge is attached to the 
taller of the cylinders, which holds the oxygen gas, and 
the other regulator is fastened to the shorter cylinder. The 
hoses, which should be cleared of all powder or scale on 
their interior, are then added. The black hose should 
connect the oxygen regulator to the torch valve, marked 
"OX" and the red hose, the acetylene regulator to the 
torch valve stamped "AC." In attaching regulators to 
full cylinders the "cross-bar" on the regulator should 
always be turned out, that is to the left, until it turns freely, 
to insure all pressure being released from the diaphragm, 
before the cylinder pressure is turned on. Another pre- 
caution that should be observed is the "cracking" of the 
cylinder valves, before attaching the regulator, in order 
to blow out any dirt or foreign particles that may be lodged 
there, otherwise they will be carried into the regulator seat, 


or lodged in some small passage, which will impair the 
working of the apparatus. Then too, if no truck or clamping 
device has been provided, both the oxygen and acetylene 
cylinders should be securely clamped or wired together, 
a rule which should be insisted upon at all times, whether in 
a job shop, manufacturing concern, or training school, or 
any place where top-heavy oxygen cylinders are being used. 
No particular harm results if these cylinders are turned over, 
which is very easily done on account of their rounded base, 
if no regulator is attached, but very frequently regulators 
are attached and the hose connecting the same to torch 
is found in the operator's way. The slightest pull or tripping 
on this hose will upset the cylinder, usually demolishing 
the regulator and expensive gauges and at times causing 
much confusion among the workmen, on account of the 
loud hissing noise given off by the escaping gas. Always 
secure the drums or the cylinders in a safe manner. 

(32) In turning on the gas, the oxygen valve is opened 
wide until seated and the acetylene valve is only partially 
opened. Often the question is raised as to where the oper- 
ator should stand, especially when dealing with high-pres- 
sure oxygen. It is recommended that the operator should 
stand at the side and towards the rear when performing this 
operation, for sometimes an unreliable gauge may be at- 
tached, which if bursting, would send the glass into the 
operator's face. 

(33) As soon as an operator has gas pressure in his regu- 
lators, he begins wondering how much pressure should be 
placed on his line, that is, the portion between the regulator 
and the torch. Of course, this depends upon the size of 
the tip, but the operator should have some means of approx- 
imating this pressure without going to his manufacturer's 
chart every time. A neutral flame, ' that is, theoretically 
equal parts of oxygen and acetylene, is desired for welding. 



Now in lighting, the flame should stand away from the 
tip a slight distance, in torches other than the low-pressure 
type, while in these there will only be a good full flame issue 
from the tip. Enough oxygen must be in evidence to bring 
this acetylene flame down to the neutral point. If not 
enough pressure is used, this result cannot be obtained, 
and of course, more pressure must be introduced. It is 
better to have too much pressure than not enough on the 
the line, for the operator may use his torch valve to again 
regulate this pressure and is always sure of enough gas. 
Theoretically, all adjustments should be made at the regu- 
lator, but in practice this is very seldom carried out. The 
accompanying cuts will illustrate the five conditions which 
every welder should be familiar with, in the flame adjustment. 
Fig. 21 shows the acetylene turned on full; no oxygen has 

FIG. 21. Acetylene Flame Blowing away from Tip. 

as yet been introduced. The flame has a yellow appearance 
and is very rich in carbon, as can be seen by the soot given 
off. In Fig. 22 we see the oxygen being turned on; the 

FIG. 22. Addition of Oxygen to Acetylene Flame. 

yellow flame (A) is gradually giving way to a white part 
at (B). In this condition we say that a feather flame exists. 
Fig. 23 shows slightly more oxygen pressure. In Fig. 24 
we have the neutral flame, which can be readily recognized 
on account of its bluish white color and well-defined out- 



line, appearing like the end of an unused piece of chalk, 
only, of course, much smaller. In Fig. 25 can be seen an 
excess or too much pressure of oxygen. It will be noticed 
that the neutral flame assumes a more bluish color, is a 

FIG. 23. More Oxygen Pressure Applied. Flame Contains Slight Excess of 
Acetylene, and is Known as "Carbonizing." 

little pointed, and a very noticeable hissing sound is in 
evidence. This is what is called an oxidizing flame and will 
be again referred to. Too much oxygen is used. Operators 
who attempt to turn on the oxygen first and then light it, 

FIG. 24. "Neutral" Flame. Correct Proportions of Oxygen and Acetylene 


will find that it does not burn, and their efforts will be useless. 
In picking up a torch for the first time, any operator can 
turn on one valve and detect by the odor of the gas, whether 
it is oxygen or the fuel gas, and can light it in accordance. 

FIG. 25. "Oxidizing" Flame. Too much Oxygen Present. 

Some operators, however, attempt to turn on a little of 
each gas and light. This is not to be recommended, for 
flashbacks may occur. When the welder accustoms himself 
to turning on enough pressure to accommodate whatever 
sized tip he may have, he will find that there is no great need 
for paying attention to the pressure gauges on his regulators 


except to check up on the full drums of oxygen, and to teli 
whether he has enough gas left to complete a certain piece 
of work. 

(34) A neutral flame is theoretically composed of equal 
parts of oxygen and acetylene ignited, but this ratio is very 
seldom worked out in practice. There is usually an excess 
of oxygen in evidence. A neutral flame is generally spoken 
of as being over 6000 degrees Fahrenheit, and this does not 
vary with the different sized. tips as most welders think. 
Of course there are different quantities of heat between 
a very small tip and a large sized one, but the temperature 
of the flame is the same. 

(35) If too much acetylene gas is used, a feather flame 
such as was seen in Fig. 23 will appear. This has a car- 
bonizing effect on the weld, for it introduces carbon and 
causes the weld to become very brittle. 

(36) If too much oxygen gas is used, the effect shown in 
Fig. 25 will take place, and the weld will have oxygen intro- 
duced, which is a very detrimental feature, and is particu- 
larly noticeable in working on steel, for it raises a white 
foam over the surface of the melted metal, which sometimes 
is worked right into the weld itself/An experienced welder 
will always know just what kind of a flame action he is 
obtaining on his weld, not because he takes the flame away 
every time he wishes to look at it, but he can tell by the 
action of his metal exactly the nature of his flame. 

(37) Infra-red (heat) and ultra-violet (light) rays present 
to a small extent in the neutral flame are injurious to the 
naked eye. Colored glasses or goggles are used to shield 
the eyes when working with this flame. Too dark a glass 
should not be used, as it will cause a strain upon the eyes 
more injurious than the flame. Exposed metal frames should 
be avoided too, as they hold the heat and burn the operator. 

(38) To shut off the . apparatus for several hours or so, 



it is best to relieve all pressure from the lines, such as hose 
and so forth, and to do this close both tank valves; open the 

(Courtesy of the Chicago Eye Shield Co.) 

FIG. 26. A Spectacle Made for Welders, having a Frame of Fiber and Arranged 
so that Lenses may be Replaced. 

(Courtesy of the Chicago Eye Shield Co.) 

FIG. 27. Showing Cover Glass which Protects the Colored Lens and the 
Replaceable Features of a Modern Goggle. 

torch valves; release the tension on the regulator, by screw- 
ing the " cross-bar" to the left, and finally, close the torch 


valves. It is quite necessary that these torch valves closed, 
for quite frequently, if a small tip is in the torch and 
an excess of oxygen pressure comes through the line, when 
both torch valves are open, much of the oxygen may back 
up the acetylene line and cause a serious flashback when 
lighting up. This can be avoided by keeping both torch 
valves closed when not in use. 

(39) If a valve on an empty acetylene cylinder is left 
open the acetylene gas will escape, and mixing with the air, 
which is a supporter of combustion, a very inflammable 
mixture will be formed. If any fire is present, such as might 
be smouldering in a forge, possibly not used for several 
hours or so, or a match lighted, or a flame started in any 
way, an explosion is likely to occur. When an acetylene 
cylinder is exhausted, as far as possible, in a moderately 
high atmospheric temperature, then shut off for a while 
and the temperature drops, air will be drawn into the vacuum 
thus formed when the valve is again opened. In this man- 
ner an explosive mixture forms in an empty acetylene cylinder 
and is certainly to be avoided. Care should be taken, 
expecially in winter, to guard against such occurrences, as 
in some outlying shops a decided change in temperature 
takes place between closing time and starting up time the 
following morning. Acetylene tanks should always be se- 
curely closed when empty, not only -for the above reasons 
but insomuch that each contains acetone, which is likely 
to escape if the tank is thrown around. Acetone is very 
costly and used extensively in the manufacture of smokeless 
powder, so that at times it is hard to replenish. 

(40) Oxygen has an affinity for oils and greases, and 
should not be allowed to come in contact with them, especially 
in confined places, as a spontaneous combustion may result. 
Oils and greases should never be used around oxy-acetylene 
welding apparatus and on nearly every apparatus on the 


market the words "Use no oil," will be found. Despite this 
precaution, however, many times ignorant operators will 
be found squirting oil into the holes around the regulator 
cap, and through the gauges, in order, as they say, to allow 
them to work easier. This use of oil should be discouraged, 
and the sooner the better. 


(41) IN equipping a shop for welding, in addition to the 
welding apparatus, the operators are many times unde- 
cided whether it is advisable to have a planed metal or a 
brick top table to use for welding purposes; each has its 
advantages, but were there a choice of one or the other, 
it is suggested that the brick-top table be used. The theory 
of having a planed metal top for lining up work does not 
prove as satisfactory in actual practice as might be expected, 
for the simple reason that the average welder generally 
places his metal in direct contact with this cold top, and 
much of the heat which is supposed to go into the weld is 
conducted away by the table top, producing a hard, brittle 
weld. In the case of cast iron, these welds are generally 
porous. Then too, the operator to a large extent depends 
upon the table top for lining up his work and does not study 
his contraction and expansion as thoroughly as he might. 
The result is that many of his pieces warp in cooling. To 
rectify the first objection it is advisable to cover the table 
top with asbestos paper as shown in Fig. 28. In the second 
place, sometimes clamps are used to hold the work in position. 
Preheating without a layer of bricks on a metal-topped 
table is not to be recommended. 

(42) A fire-brick table, made up along the lines shown 
in Fig. 29, is very easily constructed and can be used for all 
sorts of jobs. It is well to have everything clear around the 
legs and have no braces to cut the operator on the shins 




or to interfere in any way with his work. The best fire 
bricks obtainable should be used. A large number of extra 

FIG. 28. Method of Holding Heat when Welding on Metal Top Tables. 

Asbestos paper, P, is laid upon the metal top, M, and the pieces, A and B, placed upon P 
in such a manner that the weld can be made at C. The asbestos paper prevents too much heat 
escaping from the bottom of the weld. 

bricks should always be on hand for they come in very 
handy in most of the welding operations, and in fact to 

FIG. 29. A Fire-brick Table for Welding. 

Angle iron measuring 2 by 2 by \ inches is welded together in the manner shown and covered 
with fire-bricks which measure 2 i by 45 by 9 inches. 

conduct a welding shop without fire bricks could almost 
be likened to a blacksmith's shop without an anvil. Be- 
sides being used for table tops, preheating furnaces of a 



temporary nature may be built and the bricks used to jack 
up and align many jobs which could not be handled otherwise. 
(43) An emery wheel plays a very important part in a 
commercial welding shop, insomuch that rust, scale, and 
unnecessary metal can be removed in a very short time 
by its use. A flexible shaft attachment should be on hand, 

FIG. 30. One Shop in which Instruction in Steel is being Given, at the 

Ordnance Welding School. 

Note the construction of the welding tables. Two or more may be placed together, to give 
as large a surface as desired. 

if possible, or a portable grinder of some kind, for in many 
cases where the casting, or the piece being worked upon is 
too heavy to bring to the emery wheel, the wheel can be 
brought to it and many places ground down by its use that 
would be impossible with a stationary grinder. 

(44) Many times when working near a hole which may 
be threaded, the welder has much difficulty in keeping his 


metal from entering the hole. At other times it is neces- 
sary to back up preheated work such as aluminum, to 
prevent its collapsing. Ordinary clay or putty cannot 
be used for this purpose. The simple reason being that 
when metal is heated it expands and the clay or putty in 
giving off its moisture contracts, showing two opposite reac- 
tions. Retort cement is a name given furnace cement 
mixed with shredded asbestos, this, as well as carbon flour, 
has been found to be very satisfactory for filling in holes 
and backing up pre-heated work. Retort cement is purchased 
in airtight containers, hardening very quickly when brought 
in contact with the air, so at all times it should be kept in 
containers similar to those in which it is purchased. It 
cannot be reclaimed once it is hardened. 

(45) A blacksmith forge will be the medium of saving 
much valuable gas and time in a welding shop. It will heat 
up parts to be welded in very short order and while in this 
condition they may be welded and then thrown back into 
the forge and allowed to cool very slowly. 

(46) Several pails of water should always be located 
where welding is being done to prevent fire from flying 
sparks; to cool the torch tips and filler-rods, when working 
on large jobs; to keep certain parts of work being welded 
cool, and to harden or temper other parts. . 

(47) A simple and efficient manner of handling flux in 
the welding shop has puzzled many welders, on account 
of the flux containers being easily upset, their inaccesibility 
and the action of the air upon large quantities of flux. A 
simple method of overcoming this is to cut in two, a two 
and one-half or three-inch pipe coupling and mount it by 
welding on a square piece of one-eighth inch plate, as shown in 
Fig. 31. This type of container is very hard to upset* 
may be used when working on preheated jobs; is easy to get 
at on account of its shallow nature, and, as it only holds a 



small amount of flux, it can be cleaned out frequently and 
a fresh flux will always be available. 

(48) Additional equipment beneficial to the welder will 
be a quantity of various sized carbon rods and blocks; as- 
bestos paper; goggles; V-blocks for lining up shafts and 
an assortment of mechanics' tools, such as wrenches, ham- 
mers, chisels, hack-saws, and other things which might be 
used in dissembling or assembling various kinds of machinery. 

(49) Another important item which is generally overlooked 
in the average welding shop is the question of ventilation. 
Although the welding flame itself contains no objectionable 

FIG. 31. A Good Flux Container for the Welding Table. 

gases, those from fresh charcoal preheating fires, those given 
off when some of the alloys of the filler-rods are melted 
when brass, copper, and other metals are being worked on, 
and from gas engine exhausts are not desirable. At times 
they will give the operators violent headaches unless means 
are taken to carry them off. The ventilation should be such 
that it will not directly affect the work. Drafts are to 
be avoided as much as possible, for many times they will 
warp pieces being preheated if allowed to come in direct 
contact with them. It is a good thing to remember that 
indirect ventilation and plenty of it is a prime requisite 
in a good welding shop. 


(50) OCCASIONALLY in setting up a welding apparatus, a 
leak may be noticed along the lines, some time after the 
plant is in operation. Leaks on either the oxygen or acet- 
ylene lines are to be considered dangerous as well as costly 
and therefore to be avoided at all times. When the cylinder 
valves are closed on the drums containing the gases, and the 
hands on the low-pressure gauges of each regulator are 
seen to drop or reduce their pressure when the torch valves 
are shut off and allowed to remain so, this is an indication 
that there is a leak between the regulator and the torch. 
It is not desirable to use a match or a flame of any kind 
in testing for leaks. There are various methods employed 
by the cautious welder, but about the best of these is a soapy 
solution of water, which is kept in a can at all times and 
is applied with a paint brush. If this solution is applied to 
any leaky part, bubbles will form immediately and the 
leak will bt located. 

(51) At times, when working in isolated places, where 
repairs cannot be had, and no means have previously 
presented themselves for testing out the cylinders or the 
apparatus as a- whole, it may be found that the threads or 
ground seat on the cylinder valve of the regulator which 
is connected will be in such a condition that a leak is in evi- 
dence. Or it may be that the threads will not permit the 
seat being drawn up sufficiently to make it airtight. In 
cases of this kind, the welder must find some means of pro- 



ceeding with his work, and while it will be impossible for 
him to use white lead or any oily substance with safety, 
he may stop the leak with litharge or lead oxide mixed with 
a small quantity of glycerine. A string soaked in this solution 
may be wound around the main connection and the swivel 
nut screwed up to the seat as far as it will go. If allowed 
to harden for a short time, the litharge will set and a very 
satisfactory temporary repair will be effected. 

(52) The method shown in Fig. 32 of attaching con- 
nections to hoses so that they will not blow off when pres- 
sure is applied is a very simple and effective means of over- 
coming this difficulty. Undoubtedly it will assist some 
operators in solving the trouble that has been occasioned by 

FIG. 32. Method of Attaching Hose to Connection so it cannot Pull or Blow off. 

the ordinary hose clamps, especially when doing cutting or 
heavy welding work where the gas pressure is considerably 
higher than usual. The wire used should be large enough to 
prevent cutting the fabric in the hose. 

(53) An injured hose which may leak should never be 
used after the leak is noticed unless some means are taken 
to repair it. The use of tape in trying to repair hose on 
an oxy-acetylene welding outfit should never be permitted. 
The most efficient way of overcoming an injury of this kind 
is to cut the hose at this part and insert a piece of pipe. 
The ends of the hose are then wired to this pipe and a union 
is thereby effected which will generally outlast the life of 
the hose. Special connections for this purpose are put out 
by most welding companies, so that a supply may be on 
hand if hose trouble is expected. 


(54) When transporting welding apparatus, occasionally 
the " cross-bar" on the regulator is lost and many times the 
operators do not know what is to be done. The purpose 
of the " cross-bar," as we have already seen, is only to apply 
pressure on the diaphragm springs, so that if a set screw 
of the same diameter and same thread as those of the " cross- 
bar" can be found and screwed into its place with a wrench, 
a section of filler-rod can be welded across the top of it and 
the use of the regulator will not be impaired. If a special 
thread is used by any particular company, a piece of brass 
or iron can be turned down in a lathe to fit. 

(55) The manufacturers of practically all regulators use 
the quarter-inch tapered pipe thread in attaching the cylinder 
connections to the regulator and do not depend upon the 
threads being gas-tight, so they solder them in. There are 
various types of cylinder connections put out by different 
manufacturers of the gases and occasionally it may be neces- 
sary to use a cylinder of gas which contains a different con- 
nection than is supplied on the regulator. Various adapters, 
such as shown in Fig. 33, are supplied to overcome this 
difficulty, but at times the operator is confronted with the 
very embarrassing situation, of having a cylinder of gas 
and his regulator of different connections, but no adapter 
suitable. This predicament is usually found when some 
very important work is to be done and sometimes far from 
a supply depot. At times the operator may have an adapter 
which will fit the cylinder but not the regulator. If this is 
the case, his difficulty can be very easily overcome, for gen- 
erally all adapters are made of two parts, " sweated" to- 
gether, and have the same quarter- inch tapered thread as 
used in the cylinder connections on the regulator. The adapter 
can be separated, the tank connection removed and the 
correct connection " sweated" into the regulator. 

(56) Most gauges used in the oxy-acetylene industry to 


indicate gas pressure are of the Bourbon type. The most 
recent types of the oxygen high-pressure gauges are con- 
structed with a hinged back and a solid front, which means 
that should an oil or foreign matter enter the gauge from 

(Courtesy of the Bastian- Blessing Co.) 

FIG. 33. Various Types of Adaptors Used to Connect Regulators to Cyl- 
inders having Different Connection. 

any source whatsoever and tend to burst it, the back would 
be blown off and there would be no glass that could possibly 
fly around. This is a safety device which has been welcomed 
with much enthusiasm on the part of the oxy-acetylene in- 



dustry. When leaks occur in gauges, it is always best to 
remove the guage from the regulator, stopping the hole 
temporarily with a pipe plug and return the gauge to the 
manufacturers for repair. These gauges are very delicately 
constructed and can be rendered useless if handled by the 

(Courtesy of the U. S. Gauge Co.) 

FIG, 34. Showing Solid-front and Hinged-back Features of a "Safety-first" 
High-pressure Oxygen Gauge. 

inexperienced. A great many times after the case of the 
gauge has been jarred or loosened, the screws connecting 
this case to the inside working mechanism are tightened up, 
breaking the soldered connection holding the spring tube 
on the inside of the gauge. This causes a leak which can 



be repaired quite easily if the operator is able to solder it. 
It must be remembered, however, that if the flame is brought 
in contact with any of the springs that their tension will be 
lost and that the gauge may not operate correctlv after this 
repair is made unless great care is exercised. 

(57) Undoubtedly there are many welders who in begin- 
ning to operate their welding apparatus conclude that their 

FIG. 35. A 3ooo-pound High-pressure Oxygen Gauge. 

gauges must be at fault when they show a reading after 
apparently all pressure has been released in closing down the 
apparatus. It is to avoid the impression that the gauge 
is at fault that time is here taken to show that even though 
the cylinder valve is closed and the " cross-bar " on the regu- 
lator screwed out that when the torch valves are opened to 
drain the lines there will still be a reading on the high-pressure 


gauge if the regulator seat is in good working order. It is 
simply a case of gas being trapped between the regulator 
and the cylinder valve. To reduce this reading it is only 
necessary to screw in the " cross-bar," thus opening the 
regulator seat. This could be avoided if the cylinder valve 
were closed first and the torch valves opened while the regu- 
lator " cross-bar " were still screwed in, then as soon as the 
gas had left the line, the torch valves could be closed and 
the " cross-bar " on the regulator could be screwed out 
until free. 


(58) PREHEATING, as applied to oxy-acetylene welding, 
means the application of heat to the article to be welded 

(Courtesy of the Messer Mfg. Co.) 
FIG. 36. A Large Job Prepared for Welding. 

in some manner which is usually different than by the 
welding flame itself. Charcoal, coke, kerosene, crude oil, 
coal and natural gas are used for this purpose. The prin- 
cipal reasons for pre-heating parts to be welded are: To 
take care of the effects of contraction and expansion on the 
confined ends; to save time, gas, and material; and to make 



a better weld by making it quicker and with less chance of 
burning up the metal. 

(59) On account of the ductile qualities of steel, there 
is not quite as much heat used in preheating, to take care 
of the contraction and expansion, as in cast iron. On brass 
work a very dull red heat is considered sufficient, or other- 
wise the alloys might burn out. When preheating aluminum, 

(Courtesy oj the Messer Mfg. Co.) 

FIG. 37. Showing how Large Work can be Covered with Asbestos Paper 
when Preheating. 

there will be no change in color as the heat is introduced, 
so other methods are used to determine the correct tem- 
perature. Three methods are used for this purpose by most 
welders. " Half-and-half " soldering wire will usually 
melt when applied to the surface of aluminum which is 
preheated to the proper state; the puddle stick when drawn 
smartly across the heated surface should scrape off the 
oxide and leave a clear blue streak if the work is in condition 


to be welded; and if a medium-sized tip is brought down so 
that the neutral flame just touches the surface for a second 
or two, the metal will sweat, if at the proper temperature, 
and small globules which have the appearance of mercury 
will stand out on the surface. 

(60) The beginner must study contraction and expansion 
in order that he may know when and where to apply it in 
figuring out his work. Many welding jobs have turned 
out to be failures through lack of knowledge in this respect. 
Take, for example, a water-cooled cylinder block of the ordi- 
nary gas engine; the water-jacket may be broken when the 
water is allowed to freeze in it. This problem has certainly 
confined ends, but some welders have attempted to weld such 
jobs cold, that is, without preheating, and possibly have 
succeeded in executing what they thought was a very fine 
weld, but upon examination, have discovered that the cylinder 
walls, which are very accurately machined, have been warped 
to such an extent that the block is rendered useless. This 
is strictly a " preheating " job, and the cylinder should be 
brought to a dull red heat if the best results are to follow. 

As has been stated elsewhere in this volume, the weld 
should not be considered successful unless the piece worked 
upon can be returned to a usable state. 

(61) Several different fuels have been mentioned, all 
of which can be used for preheating purposes. Charcoal 
is considered the best agent for general welding, as it gives off 
a very steady heat which will gradually be absorbed by the 
article worked upon, bringing it to the heat desired and hold- 
ing it there throughout the welding operation. It will then 
permit very gradual cooling, as this sort of fire takes a long 
time in dying a desirable asset in work of this kind. On 
account of the scarcity of charcoal and its high price, other 
agencies are used and chief among them are torches using 
kerosene, crude oil, or city gas, as a fuel. These usually 



heat up the work more quickly, but care in their manipula- 
tion is necessary. A preheating torch to be used in con- 
junction with city gas can be very easily constructed, if the 
details of Fig. 38 are observed. This proves to be a very 
efficient and cheaply constructed apparatus. 

FIG. 38. Preheating Torch, Constructed of Black Iron Pipe, for Burning 

City Gas. 

(62) When work is being preheated, it is best to have 
it protected from all drafts, to prevent warping. Possibly 
the most extensively used material for building up temporary 
ovens to hold the heat and protect the work from the air 
currents is fire brick and with it asbestos paper. When 

FIG. 39. Temporary Preheating Oven, Built of Fire Brick. 

setting up an ordinary casting for preheating, these bricks 
are built up in builder's fashion, about four inches away from 
the piece itself, as shown in Fig. 39, and practically level 
with the top of the piece. If charcoal is to be used, draft 
spaces are left in the first row of bricks as shown, and the 
charcoal ignited through the openings with the welding 
torch. The work to be welded should have the line of weld 
at the top if possible and be set up from the floor, or the sur- 


face upon which the oven is resting, on one or two fire bricks, 
in order that the full benefit of the heat will be received. 
Asbestos paper is then laid across the top, and the oven will 
appear as in Fig. 40. When starting the fire, a layer of 
charcoal, a matter of two or three inches thick, is at first 
used, but as the chill is taken off the piece the oven can be 
filled to the top, and usually this is enough to complete the 

(63) In order to protect the operator, when working over 
hot fires, it is recommended that the asbestos covering be 
left on, and that only a small section immediately in the 

FIG. 40. Temporary Preheating Oven of Fire Bricks Covered with Asbestos 


vicinity of the weld be removed, which can be accomplished 
by cutting a " U " in the paper as shown by the dotted lines 
in Fig. 40. This can be turned back, exposing the place 
which is to be welded, and at the same time protecting the 
operator, to a large extent, from the unnecessary heat. 
When the weld is finished, this lap can be turned back and 
the piece allowed to cool. On pieces which require turning 
and must be welded in several different positions, the pre- 
heating oven, as it is called, should be built considerably 
larger, to provide for handling the work. , It must be remem- 
bered that during the entire operation, the piece should be 
left inside the oven and should not be removed to a welding 



table. Some beginners make the mistake of doing this. 
When welding with the charcoal in closed rooms, during the 
winter months, the fumes will be found to be very disagree- 
able and means should be taken to provide indirect ventila- 
tion, otherwise the welders will be troubled with headaches 
and smarting eyes. 

(64) When using preheating torches, the ovens are built 
much closer to the work and do not have the openings along 
the bottom row of bricks. They are made as tight as possible, 
and in some cases it will be found advisable to build up the 
walls with two layers of bricks, with asbestos paper between 

FIG. 41. Showing How Oven is Built when Preheating Torch is to be Used. 
Torch is Showi.. at (A). 

them, in order to hold the heat and cause the work to heat 
up in a more uniform manner. A hole is left in one end of 
the oven, through which the flame of the preheating torch 
is introduced as shown in Fig. 41. It is not thought best 
to have the torch flame come in direct contact with the work 
which is being preheated, and a baffling plate of metal or 
brick is placed directly in front of the flame, in order to 
spread it around the oven. Judgment will have to be used 
in all such work. 

(65) The setting up of the work, when preheating, is an 
important point overlooked by many welders, especially so 
in the case of aluminum. Care should be taken to see that the 


work has a good solid setting and is braced at a sufficient 
number of points, to prevent its sagging when in a pre- 
heated condition. Many times when working on rough sur- 
faces, a few firebricks distributed around the bottom of the 
oven with a dab of putty, clay, or retort cement, placed upon 
them, will form an excellent cushion upon which the work 
can rest and the operator may feel confident that no sagging 
will occur. 


(66) IN order to know how to weld, it is quite imperative 
that the operator first know the kind of metal he is to work 
on. It is surprising to find how few welders know their 
metals thoroughly. An incident might be cited where some 
welders depend upon the sparks given off by the emery 
wheel in determining the kind of metal they are about to 
weld. They will approach the wheel; grind off their work, 
noting the sparks; return to their welding table; choose their 
filler- rods and do their welding without any delay whatso- 
ever, much to the consternation of their fellow workers. 
There are four simple ways in common use to distinguish 
between cast iron, malleable iron, and steel; they are: By 
the cross-section of a fresh break, by application of the weld- 
ing torch, by the sparks given off when applied to the emery 
wheel and by the chisel test. 

(67) Externally cast iron usually has some sand on its 
surface and its cross-section shows the grain to t>e fine, even, 
and to have a dull grayish color. The surface of malleable 
iron contains no sand and its grain is very fine, such as cast 
iron, but slightly darker in color. A very fine steel veneer 
is on all surfaces of malleable iron, which is much lighter 
in color. When the welding torch is applied to cast iron, 
no sparks are given off, but when applied to malleable iron a 
bright spark is thrown off which breaks in falling, showing 
that the outside material is steel. These sparks soon cease 
and the metal which is molten is covered by a heavy oxide 




or skin which recedes or draws away from the flame slightly, 
showing a very porous cast-iron interior. When brought in 

FIG. 42. Characteristic Sparks of Different Irons and Steels Thrown off 
by an Emery Wheel. Wheel should be Clean Cutting and Run about 
7000 Feet per Minute. 

(1) Shows cast iron. No sparks unless impurities arc present. 

(2) Is wrought iron almost free from carbon. Heated particles thrown from wheel follow 
straight line. These become broader and more luminous some distance from their source of heat. 

(3) Illustrates mild steel action. Small amount of carbon present causes a division or forking 
of the luminous streak. 

(4) Shows the effect of increasing the carbon from 0.50 to 0.85 per cent in mild steel. The 
iron spark lines diminish: the forking of the luminous Ftreak occurs more frequently, being 
subdivided by re-explosions from smaller particles. 

(5) Is a piece of carbon tool steel. The iron lines are practically eliminated with the increase 
of the explosions and subdivisions, causing display of figures. 

(6) Gives the spark of high-speed steel, containing in addition to 65 per cent carbon, other 
alloying elements, chiefly tungsten and chromium. 

(7) Represents a manganese spark. (Occasionally found in cast iron.) 

(8) Shows spark thrown from old grade of "Mushett" steel. 

(9) Represents a magnet steel spark. 

contact with the emery wheel steel sparks, which are very 
luminous and break in falling, are given off first in the case of 
malleable iron, but they soon change to the dull red spark 



of cast iron. When a chisel is applied to cast iron, the iron 
chips off; when applied to malleable iron the edge will curl 
up, then chip off when the cast iron is reached. The cross- 
section of cast steel shows a bright, coarse, silvery gray 


Here are five methods, any one or all of which may be used to learn the 
nature of common castings which might confuse the welder. 




Malleable Iron. 

Cast Steel. 

Cast Iron. 


Generally smooth and 
free from all sand, 
weighs about same 
as cast iron. 

Rough surface 
with sand in evi- 
dence, weighs 
much more 
than cast iron. 

Surface fairly 
smooth but gen- 
erally shows 
some sand. 



Ring of bright steel 
crystals outside, 
with darker iron 
crystals inside. 

Large, bright, 
luminous, sil- 
ver crystals. 

Fine, uniform, 
dark gray, crys- 



Few steel sparks and 
then iron sparks 
from interior. 

Bright,, luminous 
sparks that 
break in falling. 

Dull red sparks 
that do not 


Chisel Test 

Surface will curl and 
interior break off. 

Will curl before 

Will chip off. 


Torch Test 

Gives way before 
flame and delivers 
few sparks. Metal 
becomes porous. 

Gives forth bright 
sparks that 
break in falling. 

Gives no sparks 
except where 
there are im- 

FIG. 43. 

grain. When the torch is applied a distinctively steel spark 
which is luminous and breaks in falling is thrown off. When 
applied to the emery wheel steel sparks are thrown off; when 
the edge is chipped by a chisel it will curl up. 


(68) The metal in the filler-rod should be the same in 
practically all cases as the metal to be welded. There are 
few exceptions to this rule, but the principal one is that of 
malleable iron. The cast iron in the rods is of a very good 
grade and generally much better than the piece to be worked 
upon. To permit the ready flow of the rod and eliminate 
oxidation, as much as possible, three per cent of silica is gen- 
erally used in the casting of filler-rods for cast iron welding. 
Piston rings and other scrap iron should not be used for filler- 
rods, as they contain many impurities s'uch as core-sand, 
dirt, grease, etc., which will ruin the weld. It is dishearten- 
ing to see some operators attempt to economize on the filler- 
rod. It is not an uncommon sight to see several dollars' worth 
of gas and the same amount of the welder's time, together 
with a few cents' worth of filler rods all lost, and the opera- 
tor's reputation ruined. This, because an attempt is 
made to save the few cents involved in the filler-rods by 
substituting a rod of a very poor grade. 

(69) A flux is not used, as many suppose, to cement the 
filler-rod to the metal. It is used purely as a cleansing 
agent and may be likened to the acid used in soldering. 
It does not act on the metal until the latter has reached the 
melting-point, but then it starts to break up the oxides and 
clean the surface. This action permits the metal to flow 
together more readily. A cast-iron flux is always used in 
welding cast iron, to break up the oxide, because the cast 
iron itself will melt before the oxide and no matter how hot 
the metal is it will not flow together as long as this oxide is 

(70) To obtain the best results, reliable fluxes should 
always be used. Occasionally an accident will happen to 
the flux can, when the operator is on some isolated job and a 
substitute flux must be obtained at once. Equal parts of 
bicarbonate of soda (cooking soda), and carbonate of soda 



(ordinary washing soda), may be purchased from any grocery 
in the powdered form and mixed together thoroughly. This 
will tide the welder over until he can return to the shop and 
replenish his supply. 

(71) The flux is generally applied by means of the filler- 
rod. One end is heated and dipped in the flux; enough will 
adhere to break up part of the oxides, on the ordinary-sized 
job. The flux is carried to the work, which should be at the 
melting-point and introduced between the flame and the metal. 
Oxides will break up immediately and the metal will flow 
together, but it must be remembered that the flux has no 

FIG. 44. Whenever Possible, the Beginner should "V" His Work, and Com- 
plete His Weld from One Side only. On heavy work, however, it will 
be necessary to " V" out from both sides, as is here shown. 

action on cold or moderately heated metals. The flux as 
has been explained is used to clean the metal and break up 
the oxides. To the oft-repeated question, how often should 
the flux be applied, answer is made as follows: As often as 
it is necessary to clean up the metal and break up the oxides. 
All fluxes should be kept in airtight containers when not in 
use, to keep their chemical contents in the very best condi- 
tion and it is best to use only a small quantity of flux on the 
welding table at one time. 

(72) Oxy-acetylene welding is purely a fusing process 
and the most important points to remember in executing 
a weld are, to eliminate the entire crack in the fracture and 


to add the filler-rod without changing the character of the 
metal. On thin pieces of metal it is possible to depend upon 
the force of the flame to entirely penetrate to the depth of the 
crack but on work three-eighths of an inch thick or over, it 
is well to " V " out or remove some of the surface metal around 
the crack in order to get down to the bottom. By " V-ing " 
we mean to chip or grind off each edge at an angle of 
approximately 45 degrees, so that the opening will form an 
angle of 90 degrees where the two pieces come together, 
with the crack at the bottom portion of the " V." This should 
NOT be ground down to a knife edge, for it will readily burn 
up. It is preferable to leave about one-eighth inch along the 
line in order that the pieces will fit together and the proper 

FIG. 45. Starting a Cast-iron Weld. 

alignment may be obtained. If two pieces of cast iron have 
been prepared in this manner the neutral flame of the welding 
torch is brought down in such a manner that the tip of the 
cone just licks the metal. The heat is not applied directly to 
the line of weld to start with, but rather to the surrounding 
part. This is done in order to get the entire locality in a con- 
dition which will not withdraw too much of the heat from the 
line of the weld, once the fusing is begun. If it is found that 
the tip will not produce enough heat to bring the metal to a 
red heat in a fairly short time, a larger tip should be used. 

(73) No set rule can be given as to the sized tip to be used 
on various kinds of metal. It will largely depend upon the 
welder's ability and judgment. When the metal is brought 


to red-heat, the neutral flame or cone is brought into contact 
with the lowest portion of the "V" and held there until 
it is seen that the metal is, melted on both sides. The filler- 
rod, which has previously been heated at one end and dipped 
into the flux so that an amount adheres to the end of the rod, 
then carries this flux to that portion of the weld which is 
under way. Enough flux is blown off the rod into the weld 
to clean up the surface and permit the metal flowing together. 
The crack should be melted together all along before any 
additional metal is added, for the elimination of the crack is 
extremely important. It might be noted that as soon as the 
metal begins to flow freely the neutral flame should be raised 
a short distance from the work in order to better control the 

FIG. 46. Reinforcing a Cast-iron Weld. 

molten metal. In order to build up the metal to the original 
state along the line of weld or perhaps 'reinforce it, the sides 
and bottom of this " V-ed " out part are then brought to a 
molten state arid held there while the filler-rod which brings 
up more flux is stirred into this metal and the end melted off. 
In this way the flame does not come in direct contact with 
the filler-rod and is used only to keep the metal in a molten 
condition. As much of the filler-rod can be melted off as is 
thought necessary to bring the weld to the normal condition 
of the metal or an additional reinforcement can be built up, 
if it is thought advisable. If care is taken in the above pro- 
cedure, many of the blow holes and hard spots in the weld will 
be eliminated, for any impurities that might gather will be 


displaced by the melted metal and will float to the top. 
In cooling a weld of this kind, care should be taken not to 
permit any sudden chilling for this will tend to harden the 
weld. It is best to cool it slowly by burying it in slack lime, 
ashes, or wrap it with asbestos paper to keep the air from it 
as much as possible. 

(74) There may be a great many causes for blow holes and 
hard spots in the weld, but probably they can all be traced 
directly to the lack of heat. It must be remembered that 
welding is a fusing process and heat is absolutely essential. 
Therefore it should not be used sparingly. The application 
of heat always causes expansion. There are no exceptions 

FIG. 47. This Problem does not Require Preheating to Care for Contraction, 
as the Ends of A and B. are not Confined. 

to this rule, likewise upon cooling the metal there will be a 
contraction. Outside of the actual welding, that is, the 
fusing of the metal into a homogeneous mass, perhaps the 
greatest problem that the welder has to confront is the expan- 
sion and contraction of his metals. Whenever the ends of 
two pieces of metal which are to be welded are free to move, 
or even one end, there will be no difficulty encountered with 
contraction and expansion, but if these ends are confined, it 
is an entirely different problem. 

(75) To illustrate this point more clearly, the following 
very simple example will be given. In Fig. 47 we have two 
bars of metal A and B which have been beveled off or " V-ed " 



out as shown at the point C. Now as soon as the heat is 
introduced at C there is bound to be an expansion of the metal 
at that point. Naturally if the pieces were heated slowly 
and for a considerable distance, the cool ends of these bars 
would be forced outward. We will assume that the heat is 
introduced very rapidly and the metal is brought to a molten 
state; that instead of the contraction forcing the cool ends 
outward, whatever expansion there is, is taken care of, 
at the weld, for the metal when melted will readily push to- 

FIG. 48. Preheating Problem. Ends ofvBars A' and B' are Confined. 

gether. It is also assumed that the bars are heavy enough to 
overcome what slight force might be in evidence from the 
expansion. A weld is then made and allowed to cool. As 
it cools, there is bound to be a contraction along the line of 
the weld and the welded piece will be slightly shorter than the 
work before the weld, for it will draw in the pieces A and B. 
As can be seen, there is no particular force preventing the 
contraction of such a weld for the ends are free to move. 
However, let us turn to Fig. 48, which constitutes an entirely 
different problem. It might seem that the ends A' and B r 


appear the same as A and B in Fig. 47, but such is not the 
case. The ends farthest from the weld are confined, held in 
place by a heavy frame which does not permit their free 
movement. When heat is introduced at the point of welding 
C", about the same action takes place as in the previous 
problem, but as soon as the weld commences to cool let us 
see what happens. The bar A'B' must be shortened so there 
is an inward pull on the bars D' and E' '. If this work were 
cast iron or aluminum it would certainly be broken by the 
strains set to working and would naturally break at C', where 
the metal is still hot. If it were steel or one of the ductile 
metals, it might twist and warp in its endeavor to overcome 
these internal strains. This illustrates in a very simple 
manner the difference between what is known as a " cold " 
and a " preheating " job. In the first no provision is made 
for expansion and contraction. In the second means are taken 
to overcome these important factors. In order to provide 
for the successful welding of the second problem, it is only 
necessary to heat up the bars X and Y about the same distance 
as the center will be heated, and keep them in that condition 
while executing the weld atC', then allowing the whole to cool 


(76) BEFORE commencing to weld, or even turning on the 
gas, it is well to see that all preparations have been made and 
all materials on hand to bring the weld or whatever job it 
may be, to a finished state. 

(77) As a specific example of a simple welding operation 
let us consider that two cast-iron bars, measuring one by six 
inches and twenty-four inches long are to be welded end 
to end. To start with it would be necessary to " V " off the 
?nds that were to be joined at an angle of about 45 degrees, 


leaving about one-eighth inch along the bottom edge to line 
the metals up with and to see whether they are in proper 
position. If the bar were to measure exactly forty-eight 
inches when finished it would be necessary to move these 

(Courtesy of Ben K. Smith, U. S. Welding Co.) 

FIG. 49. This Locomotive Cylinder was Welded at the Saddle, near the 


bars apart about one-sixteenth of an inch in order to provide 
for their contraction. It is assumed that the weight of 
the bars would be sufficient to prevent their pushing apart 
when the line of the weld is brought to a molten state and that 


the expansion will be taken care of within the weld. The 
bars after being lined up are ready for welding, but there 
are such things as filler-rods, flux and goggles that are neces- 
sary to have on hand before starting to work. It is well 
to have a few fire bricks, a little asbestos paper and a bucket 
of water convenient, in case these things are needed. The 
acetylene gas should then be turned on and ignited. A suf- 
ficient pressure should be passing through the regulator, when 
using a medium, or high-pressure apparatus, to cause the 
flame to leave the torch tip about twice the distance of the 
diameter of the orifice of that particular tip. Then turn on 
the oxygen until a neutral flame is obtained. On some 
torches it is necessary to make a second adjustment by 
turning on a little more acetylene gas and still more oxygen, 
until a goodly sized neutral flame results. Apply the flame 
to the pieces, so that the neutral flame will just lick the sur- 
face of the metal. Move the torch slowly forward and back- 
ward on each side of the " V " until the two edges are a dull 
red color, or better still a bright cherry red, then hold the torch 
stationary until the metal in the " V " nearest to the operator 
commences to melt. Then bring the filler-rod end in contact 
with the flame to get it heated and plunge it into the flux 
which should be near at hand. Enough flux will adhere 
to break up the oxides and by placing the rod between the 
flame and the metal, enough flux will be introduced to allow 
fusing of the metal. Proceed in this manner until the metal 
in the bottom of the " V " is properly fused throughout 
its length. Do not add the filler-rod, up to this point unless 
necessary. In holding the flame, see that the preheating 
flame will heat the parts yet to be welded. The weld should 
be made away from the operator. After the metals along 
the bottom have united and a good foundation has been 
obtained, then start the weld at the beginning once more, 
working the flame across the piece, in the same manner as 


before; bringing the metal to the molten state and stirring 
the filler-rod in it. As the filler-rod melts, the amount of 
molten metal naturally increases and the flame is moved 
along the weld as fast as the metal is added. It is important 
that the metal is in a molten condition. It is almost im- 
possible to get too much heat on this type of work. Build 
up the weld slightly higher than the original piece. It may be 
found in finishing up the corners that the velocity of the gases 
or the force of the flame will be sufficient to blow the melted 
metal away. This may be overcome by directing the flame 
at a different angle, and will cause no difficulty after a little 
practice. Trouble, too, may be experienced on thin cast- 
iron sections by having the metal collapse through the force 
of the flame, but this can be remedied in the same manner. 
While the weld is still in a heated condition, it is possible to 
finish it by scraping the surplus metal off with the side of the 
filler-rod, the chill of which has been taken off before it is 
allowed to come in contact with the molten metal. Another 
popular method that will produce even better results is to 
use a very heavy rasp file to bring the weld down to the meas- 
urements desired. During all of the previous operations the 
flame never leaves the line of weld. When the weld is com- 
pleted, the torch is shut down by turning off the oxygen 
first, and then the acetylene, and the welded bar is covered 
up to prevent its cooling too rapidly. 


(78) PROBLEMS in expansion and contraction should not 
be difficult, if it is remembered that heat causes expansion 
and the withdrawal of heat, or cooling causes contraction. 
As previously stated, when the ends of the pieces which are 
being welded are free to move, there is not much danger of 
having contraction strains set up. Where the ends are con- 


fined, measures must be taken to overcome this. In welding 
large pulley wheels, for example, it may be advisable to do 
the job without taking time to preheat. Breaks may be 
in evidence at any part of the wheel and generally the ends 
are confined, such as in the case of a spoke. If it is borne in 
mind that the expansion will take care of itself, the contrac- 
tion is the only consideration, in a case of this kind. The 
welder will see that if he can spring the edges apart a sufficient 
amount to provide for the spoke coming back to normal when 
welded, he will have no difficulty. The way to proceed in a 
case, of this kind would be to open the rim by sawing it and 
then introduce a jack or some sort of a wedge between the 
hub and the rim. This will open the crack in the spoke the 
amount desired. As soon as the weld is executed and while 
still hot, the jack is removed to permit the rim being drawn 
in. Later the rim can be welded, by introducing jacks be- 
tween the spokes and the same procedure followed. It 
always must be remembered that provision must be made 
for the contraction, even though it be only one thirty-second 
or one-sixteenth of an inch. The distance will depend en- 
tirely upon the welder, as some operators use small tips and 
cover a small area, while others employ larger tips and cover 
twice the area. It is therefore impossible to set any specific 
distance and each welder should try to figure this out for 

(79) There are many jobs not of a preheating nature 
that at times cause perplexity on the part of the welder. A 
good example of this is a cast-iron gear wheel. A number of 
its teeth have been broken out. Now there are three very 
common ways of building up or repairing such castings. 
First by aid of carbon blocks, cut to form and the teeth cast 
in by the use of the torch; second, by blanking in the space 
between the teeth and then sawing out the individual tooth 
or cutting it out with a milling machine or shaper; third, by 



building up each tooth with the welding rod and torch, 
and later dressing it down with a file. One very important 
point must be uppermost, when dental work on gears is being 
done, a good foundation is necessary, for regardless of how 
well the tooth may be shaped, if it is not firmly secured to the 
wheel itself, it will be of very little value. Another very 

eld Eqttipment Co.) 

FIG. 50. Large Cast-iron Gear Wheels. Although the Face on These Gears 
Measured 10 Inches, New Teeth were Added by Blanking In, as Shown 
in the Right-hand View, and Later Machined. 

important point is in the finishing of such gears, to see that 
the teeth which have been added correspond in the pitch 
and mesh exactly as the others do. The importance of seeing 
that things of this nature are machined correctly should not 
require mention, but it has often been found that machinists 
are very careless about finishing this kind of work and if 


anything goes wrong, the welder is naturally at fault. There- 
fore it is always well to put the gears which have been welded 
back into place and turn them over slowly by hand to see that 
they are in good condition before the power is turned on. 
In allowing this kind of work to cool after it has been welded, 

(Courtesy of the Oxweld Acetylene Co.) 

FIG. 51. This View Shows new Teeth being Welded in an 8^-ft. Cast-iron 
Gear, Weighing over 5 Tons. Note the Improvised Preheating Oven. 

some operators permit it to be hurried, with the result that 
there may be hard spots to confront the machinist when 
finishing. If he ruins one or two of his cutters he will naturally 
frown upon all welding work. It is therefore desirable for 
this and many other reasons to have the weld come out as 


soft as possible, and great care should be exercised in cooling. 
Any weld that is subjected to machining, allow it to cool 
slowly in slack lime, in ashes, or cover it securely with asbestos 
paper. Occasionally it may be found difficult to find sections 
of carbon blocks which will take care of a job of this kind. 
Many welders who have had to run around the country, 
and do jobs in isolated places, have found that the carbon 
centers, from the ordinary dry cell batteries, which may be 
found practically everywhere in a discarded condition, can 
be shaped on an emery wheel and patched together in a manner 
that will permit their use. However, when such are used, 
it is quite necessary that they be heated a little with a torch 
beforehand, in order to drive out any chemicals or acids 
that may be contained in them. Unless these chemicals are 
removed, the molten metal coming in direct contact with 
them might be injured to a considerable extent. 

(80) Ofttimes there are castings upon which parts wear 
off in a very short time. There may be very little strain 
upon these parts, yet the constant wear will weaken them in 
time. It is well to remember the action of a carbonizing 
flame when executing work of this kind. Introduce an 
excess of acetylene when finishing up the work. It will be 
found that with a strongly carbonizing flame, carbon will 
be taken up by the molten metal and the finished weld will 
be considerably harder and will wear longer than if it were 
executed by a neutral flame. An abrupt cooling will chill 
the metal on the surface and make it wear longer than it 
would otherwise. 




(81) THE true index as to the success of a weld will depend 
entirely upon the finished job. If it is usable, i.e., if it can 
be put back into service again and give satisfaction, it may be 
considered a successful weld. If a piece were to be warped, 
distorted, contain hard spots which could not be machined, 
or have internal strains, which would not make it safe for 

(Courtesy of Ben K. Smith, V. S. Welding Co.) 

FIG. 52. View of Locomotive Cylinder with Three Jackets 3 Inches Thick. 
This job weighed over 16 Tons and Required Fifty-six Hours of Welding. 

use (such as fly- wheels), it could not then be considered 
satisfactory and it would be only wasted energy. Perhaps 
one of the most common jobs in the ordinary commercial 
shop, and one which is the most abused, is the common cast- 
iron cylinder block found on the gasoline engine. This is 
so constructed that there are two walls of metal, very thinly 
cast; the innermost being the cylinder wall, and the outer- 


most a water-jacket. The cylinder wall is machined very 
accurately to accommodate pistons moving at a very rapid 
rate, up and down and yet holding compression. The 
upper part of the cylinder is called the head, and generally 
has two or more valve seats which must be in alignment 
with the valve guides to make an airtight seat for the valves. 
Now this water-jacket is usually very thin, perhaps three- 
sixteenths to one-quarter inch in thickness, and when there are 
two, three, four, or more cylinders cast in one block, there are 
bound to be internal strains set up in casting within the 
piece itself. These strains are removed to a large extent 
by baking the rough casting before machining. Generally 
there are some strains left in every cylinder block of this 
nature. If the water in the water-jacket freezes or some 
other force comes in contact with the thin castings which con- 
stitute a block, the metal will give way at its weakest point, 
and the welder is usually called upon to repair it. At times 
these cracks are exceedingly small and the temptation is to 
braze or attempt to weld the small portions. However, 
as soon as there is heat introduced into the water-jacket and 
not into the cylinder wall, there are certain to be strains set 
up which, if sufficient, will distort the cylinder and make it 
useless unless it is rebored. The sooner welders realize that 
work of this nature must be preheated throughout, to a 
point as near melting as they can approach without causing 
the metal to scale, before any welding is attempted, the 
better success will be obtained in these lines. It is quite 
necessary to line up the work well, so that it will not sag 
when heated. It is best to heat very slowly and cool in the 
same manner to insure the best results. There are many 
preheating agencies, such as oil-ovens, preheating torches 
and the like, but about the best and most reliable agent 
known is charcoal, which heats up very gradually, makes 
a good even fire and dies down slowly which is the manner 



"'- -U-- 


desired. Occasionally cracks will be found in the combus- 
tion head of the cylinder. It is very difficult to get the 
torch down inside the cylinder to execute this weld unless 
the operator has a special torch for this purpose. Even then 
it is difficult to keep the torch lighted when working over a 
newly made charcoal fire. For this reason, other means 
must be used when working on a job of this kind. First 
the crack is accurately located, then a piece is cut out of the 
water-jacket just over the crack by means of a chisel, hack- 
saw or drill press. Never attempt to remove a piece of this 
nature with the flame, for the introduction of heat may dis- 
tort the piece at this time. " V " out the crack in the com- 
bustion head and scrape off as much of the brown oxide and 
dirt formation as possible. It is well to clean off more than 
needed and to even " V " out the crack a greater distance than 
is thought necessary. This will insure a good weld being 
made in one operation. The cylinder is then preheated with 
the crack uppermost so that welding can be executed with the 
least possible difficulty. While preheating is taking place 
it is well to tack the small section of the water-jacket which 
has been removed, to the end of the filler-rod, and place it 
too, in the preheating oven, with the end of the filler-rod 
projecting so that it will be available whenever needed. 
When the cylinder is red hot the weld should be executed; 
particular attention being given to see that each part of the 
metal is actually fused to prevent any leaks occurring later. 
As a rule the welder can tell when he has made a successful 
weld by observing the flow of his metal, and it will not be 
necessary for him to test out this cylinder weld before adding 
the water-jacket. The piece of the water-jacket is then 
replaced; it can be very easily handled by means of the 
filler-rod which has been tacked on. Weld this section securely 
in place and cover the piece of work with asbestos paper and 
permit it to cool with the dying fire. When cold, all port 



holes in the water-jacket should be closed and the cylinder 
tested for leaks. This can be done by introducing water 
into the water-jacket and applying 
about fifteen pounds of air pressure. 
Wet spots will appear if there are 
any leaks. If the cylinder is found 
tight it should be polished, then 
oiled, and the outside given a coat 
of filler or painted to make it pre- 
sentable. Work is generally very 
much discolored when coming out 
of the fire. A simple device for 
polishing the cylinder bore may be 
made by turning out a hardwood 
block about three inches long and FIG. ^.-Suggested Method of 
a little less in diameter than the Polishing Cylinder Walls of 
size of the piston. This should be Cast - iron Cylinder Block 

,. . -r^. after it has been Preheated. 

split as shown in Fig. 54, and 

FIG. 55. Cast-iron Cylinder 
Block with Part Broken 

FIG. 56. Showing how Broken Part 
on Cast-iron Block should be Lined 
up before Welding. Position Great- 
ly Exaggerated. 


wrapped with very fine emery cloth, then put into the cyl- 
inder and a wedge placed between the two halves. Spread 
them apart so they will come in contact with the cylinder 
wall on all sides. A screwdriver may be used for this purpose 
if necessary. By screwing this into the cylinder its full 
depth, with the aid of a little oil, a very highly polished 
surface may be obtained. 

(82) Another cylinder block job that generally causes 
more confusion than is necessary is brought about when 
welding on small lugs, such as shown in Fig. 55. When 
welding these lugs on from the outside only, they generally 
warp upwards in cooling and it is either necessary to build 
up the bottom side of this lug or to machine off the entire 
face in order to have the end square. This can easily be 
overcome by permitting the lug to sag before welding and 
then dress off the small portion that continues to sag, after it 
is welded, rather than face off the whole surface, See Fig. 56. 


(83) THE term " steel," as used in the following pages, 
unless otherwise specified, will be the term applied to wrought- 
iron and low-carbon steels. High-carbon and alloyed steels 
are to be considered only in advanced work and will therefore 
not be deemed a topic of interest to the beginner in laying 
his foundation. 

(84) The welding of steel is much more difficult than cast 
iron on account of the many points which must be observed. 
In cast iron the metal is brought to a molten state and may be 
worked in that condition for some time without any apparent 
change in the characteristics of the metal. A flux is used 
to break up the oxide or scale and the metal will flow very 
easily. The flux is necessary because the oxide has a higher 
melting-point than the iron itself. When working on steel, 
it will be observed that just the reverse is true, that its oxide 
has a lower melting-point than the steel and consequently 
no flux or cleaning powder is necessary when working upon it. 

(85) A large quantity of steel kept in a molten condition 
by the flame acting upon it is very easily influenced. The 
same area is not kept in a molten condition as with cast iron. 
The heat does not hold to the vicinity of the weld nearly 
so much as in cast iron because of the greater conductivity 
of the metal. If the flame is removed, the molten metal will 
set almost immediately. This means that the flame must 
be in contact with the metal at all times. It must be a 
strictly neutral flame or else one of the two gases will be intro- 



duced into the weld and its strength will be materially affected. 
The size of this flame must be such that too great, an area 
will not be covered, yet enough must be covered to keep the 
metal along the line of the weld in a molten condition. If 
a carbonizing flame is used, one which has an excess of acety- 
lene, such as was shown in Fig. 23, much carbon will be taken 
up by the metal, producing a brittle weld. If the flame is 
oxidizing, that is, contains an excess of oxygen which is noticed 
by the shortening of the flame and an accompanying hissing 
sound, Fig. 25, the metal will burn and a white foam will 
appear on the weld like a milky white glue. This tends to 
weaken the weld. This same effect will be in evidence if 
too large a tip is used. On the other hand if the tip is too 
small not enough heat is obtained and the oxides and other 
impurities which may be present will not be allowed to float 
to the surface but will be trapped in the weld. 

(86) The filler-rod used on steel should be as near the 
same grade, if not better than the metal to be welded and 
should be very low in its carbon content. A pure grade of 
soft iron wire or mild steel will make a very good filler-rod 
for ordinary purposes. The size of this filler-rod is very 
important, for it should fuse at the same time as the metal 
being worked upon, and unless it does this the weld will not 
be satisfactory. If the filler T rod is too large it will not be 
at the fusion point when the work is, and will not fuse with 
it. If the rod is brought to a melting-point the work will 
have too much heat and will burn. On the other hand, 
if the filler-rod is too small, it will burn up before the work 
is at the fusion point, or in other words, the work will still 
be too cold when the rod is melted. 

(87) There are many different methods of executing a 
steel weld, and it has been noted that very few experienced 
welders handle their steel in the same manner. Most of these 
methods are very difficult to learn and can be perfected only 


after years of practice. However, a simple method which will 
produce results is thought the most advisable for the beginner. 
A careful examination and study of this point has brought 
out the following method, which is very easily picked up and 
which dispenses with most of the torch movements that are 
generally advocated by the old time welders. 

(88) When welding two pieces of steel bars, the cross- 
section of which will measure one-half inch by three inches, 
they are beveled off and prepared in the manner illustrated 
in Fig. 57, either by means of a chisel, file, or by the use of a 
grinding wheel. About an eighth of an inch of the original 

FIG. 57. Preparing and Heating Steel before Welding. 

stock is left on the bottom side and the angle formed from 
these two places when brought together, should be 90 degrees. 
When the pieces have been prepared and placed in the posi- 
tion shown in the illustration,- the neutral flame is then 
brought down at right angles to the plane of the metal, so that 
the end of the cone will just lick the surface. It is moved 
up and down upon each side of the part to be welded until 
each piece is brought to a red heat, for a distance of at least 
one inch back. The position of the torch during this opera- 
tion can be seen in Fig. 57. From this time on, the operator 
should work as rapidly as possible, for the quicker the fusion 


of the metal is brought about, the less oxide or scale will 
appear and a better weld will result. The description of 
this process may take some length but the actual fusion not 
nearly so long. 

(89) When the red-hot stage is reached, the neutral flame 
is brought down to the very lowest part of the " V " at the 
side nearest the operator and held there until the metal has 
melted and is about to collapse. The flame is then quickly 
twisted away for just a second to let the metal set. Perhaps 

FIG. 58. In Welding Steel, the Beginner Should Fuse His Pieces together 
aldng the Bottom with the Torch Flame, Adding no New Metal. The 
Metal on Both Sides of the Torch Flame is Melted together until a Small 
Pool of Molten Metal Appears, then the Torch is Twisted Smartly away, 
as Shown by the Arrow, and the Metal Allowed to "Set" for an Instant 
before Proceeding along the Line of Weld. 

this operation will fuse about one-half inch or less along the 
bottom of the " V." This same operation is repeated along 
the line of weld until the whole piece is fused along the bot- 
tom. It will be noted that no filler-rod has as yet been used. 
After the last portion has been fused, the flame is brought 
back to the starting-point and played not only on the bottom, 
which has already been fused, but on the sides of the " V " 
as well, bringing an area of about one inch in diameter to a 
molten condition. The tip of the welding torch is held in a 
vertical position all this time to Introduce as much heat into 


the weld as possible. During this operation the filler-rod, 
which should measure three-sixteenths or one-quarter inch 
in diameter, is picked up by the operator's free hand and its 
end brought near the heat of the flame so that it may be 
warmed and will not chill the metal when introduced into the 
weld. When the melted metal is running freely, the tip of 
the welding torch is slowly inclined in the direction of the part 
to be welded and is advanced along the " V-ed " out portion 
at this angle as rapidly as the metal can be made to melt. 
This position is shown in Fig. 59. It will be noted that 

FIG. 59. Method of Adding "Filler-rod" in Welding Steel. Note that the 
Rod is Worked behind the Flame. 

as the flame advances along the line of the weld the molten 
metal will mount up behind it of its own accord, providing 
the metal is in a molten condition, when the flame passes over 
it. During this period the filler-rod is stirred into the molten 
metal in a circular movement which should be in back of 
the torch as much as possible. This means that the torch 
comes in contact with the filler-rod but very little and the rod 
is melted, not by the flame, but by the molten metal of the 
piece being welded. It will be noticed at times, when too 
much metal has been welded and the torch is not advancing 
rapidly enough, that some of the molten metal will run ahead 


of the flame, into that part of the " V " yet to be fused, and 
to the unwary student this will be looked upon as a safe place 
to add his filler-rod. However, when the piece is broken 
and the cross-section of the weld examined, it will be found 
that in this part of the weld, the metal has only been laid on 
and not fused. The beginner should watch this operation 
and see to it that this molten metal is not permitted to run 
ahead of his torch, an act which he can overcome by the proper 
manipulation of his filler-rod, which really governs all the 
melted metal behind the flame. If not enough metal has 
been added to fill in the " V " to the proper thickness, this 

FIG. 60. This Method of Adding the "Filler-rod" when Welding is not 
Recommended for the Beginner. 

operation can be repeated until enough metal has been added. 
By practicing this method the student can be taught to 
execute a very successful weld and reinforce it all in one 
operation without any chance of burning his filler-rod or 
lapping his metal. More practice is required to successfully 
weld steel than most other metals and the beginner should 
not be discouraged if it takes him some time to conquer this 
metal. It should be forcibly impressed on the student 
that the metal must be in a molten condition before the filler- 
rod is added, or else it will stick and prevent his working 
readily and in addition will produce a very faulty weld. 


Fusion is the thing to bear in mind for without it success can- 
not be expected. 

(90) While outside appearances should not be considered 
as a prime requisite, when beginning it is always well to add 
more metal than is really necessary in order to reinforce the 
weld as much as possible. It cannot be expected, however, 
that a steel with the same cross-section as the original will 
possess the same properties and be as strong, for a weld is 
only a casting unless treated otherwise and the steel or wrought 
iron used in the specimens is of rolled stock. If too much 
metal has been added and dressing down is necessary, the 
student will find that by using a slightly oxidizing flame the 
surplus metal can be burnt away very rapidly and a very 
good-looking job can be executed much more rapidly than if 
a neutral flame were used. It is well to remember, however, 
that this is used only in dressing off pieces and in places 
where the strength of the weld is not to be jeopardized. 

(91) When advancing in steel work, it will be noticed that 
the same provision for contraction and expansion is not con- 
sidered in as great proportions as on cast iron, and the reason 
is quite evident. In cast iron we find the metal is very 
brittle and will not give without breaking, whereas on steel 
it is more ductile and will twist and bend before breaking. 
This does not mean, however, that the important points of 
expansion and contraction are to be neglected in steel work, 
for they are very important; as we shall see later on. 


(92) IT is still supposed that the beginner knows very little 
about the various kinds of metals, or methods of distinguish- 
ing between them. This is of great importance and should 
at once be overcome, as he will not at all times have someone 
over him to diagnose his case and tell him the proper procedure. 


For instance, were he to be given a piece of cast steel to weld, 
thinking that it was cast iron, he would use a cast-iron 
filler-rod in executing his weld. The results of such a weld 
would not be very favorable, and the same would hold true 
if a steel filler-rod were used on cast ifon. An occasional 
glance at the table in paragraph 67 will acquaint him with the 
various tests to make when deciding upon the nature of 
the piece to be worked upon. The tests should be applied 
in every doubtful instance. When working on cast steel, 
a student may think that he must have a cast-steel filler-rod, 
but this is an exception to the general rule and he can use 
the same style filler-rod as he would employ on ordinary 
steel work. It might be mentioned here that when working 
on alloyed and high-carbon steels, the filler-rod generally 
contains some of the alloy or carbon which will tend to 
replace that destroyed by the action of the flame in the origi- 
nal metal. 

(93) In welding cast steel the same procedure takes place 
as -previously described for steel, and it should present no 
real difficulties after that process is understood. There may 
be more sand, oxide and other impurities present on account 
of the nature of the metal, but these can all be worked out 
if plenty of heat is applied. At times, when working in steel, 
it will be found that there may be a small hole develop in 
the center of the weld and as the torch is worked into this 
hole it is found that it goes down a short distance and seem- 
ingly refuses to be worked out. This is what most welders 
call a " crater," and is caused by the metal at the bottom 
not being hot enough for the surrounding melted metal to 
fuse it. When found they should be removed before adding 
any more metal. By playing the torch flame around and 
around it, so that the heat may be transmitted to the bottom 
of the " crater " and it brought to the melting-point like 
the surrounding metal and suddenly jerking the torch away, 


it will disappear. " Craters " are generally formed during 
the first part of the weld, especially if the " V " is narrow, 
and they are hard to handle when deep. Under no circum- 
stances should the filler-rod be melted into them in trying to 
make them disappear, as this will only mean covering them 

(94) Some welders find that hard spots develop in their 
welds which they have difficulty in overcoming, and it is a 
very serious handicap when the weld is to be machined, for 
ofttimes it will break very expensive tools and leave a 
portion of a drill or die broken off in the metal. It is prob- 
ably safe to say that the principal cause of hard spots in steel 
welds is due to lack of heat. This, if given careful thought 
and consideration, will be brought home forcibly to the welder 
as he proceeds in his work, for the lapping of metals, trapping 
of oxides, " craters," too rapid cooling, etc., may all be 
directly attributed to a lack of sufficient heat. If the metal is 
in a molten state, all impurities will be brought to the sur- 
face, for they are bound to be displaced by the weight of the 
metal, the same as corks in a barrel will float to the top if 
water is introduced. The water in this case has a greater 
specific gravity than the corks. 

(95) In welding on sheet iron and steel, many operators 
will find that they have more difficulty in executing a suc- 
cessful weld than on slightly heavier work. This is no 
doubt due to the thin nature of the work and the ease with 
which it may be burned or carbonized if the operator is not 
alert. When working on such material a very small filler- 
rod is used if thought necessary but this rod must be as 
free from impurities as possible. When working on a long 
seam such as may be encountered on a steel tank, it will be 
noticed that in welding from one end along the seam that the 
metal ahead of the flame will tend to overlap as shown in 
Fig. 61. This may be overcome by tacking (that is, fusing 


the metals together), at various points before starting the 
weld, or the parts ahead of the torch can be separated as is 
shown in Fig. 62 and held this way by using a wedge. This 
is moved along as the weld advances and permits the edges 
to close together. Another method used by manufacturers 
who make a specialty of this work is to construct a jig which 

FIG. 6 1. The Open Ends on long Steel Welds will Overlap as the Welding 
Progresses if Improperly Started. 

FIG. 62. Showing how Open Ends of Steel pieces are Spread Slightly to Over- 
come Lapping of Ends in Making Weld. 

clamps the ends rigidly and they are welded while in this 
position. This phenomenon in steel welding will appear 
rather strange to the welder who has had some experience on 
thin cast-iron work, such as oven doors and the like. In 
these he found that as his weld advanced, the welded portion 
before him would separate, and when he had welded about 



four inches or so it would be necessary for him to jump his 
flame back to the beginning of his weld and heat up that 
portion, in order to close up the cracks before him previous 
to his continuing the work. This is illustrated in Fig. 63. 
This may be explained by the fact that steel is a very 
ductile metal and when it is fused, the expansion is taken 
care of internally by the two edges combining. Then, in 
cooling, the metal contracts, an action much more rapid in 
steel than in cast iron, and draws the edges of the steel plates 
past each other so that they overlap. In cast iron, which is 

FIG. 63. This Illustration Shows how the Open Ends of Thin Cast-iron 
Pieces Spread apart as the Weld Progresses. To Close the Edges to- 
gether, Jump the Torch Flame from B to A; as A heats up, B Cools 
and the Lever-like Action Closes the Opening. 

rigid, the edges are expanded by the fusion of the metal and 
this space is then filled up with new metal, holding the edges 
apart. As the weld progresses the metal ahead of the torch 
is pushing out, and that behind is cooling off, which acts as 
a lever on each side to open up the unwelded ends. 

(96) To weld a broken automobile frame successfully 
the body of the car should be raised if necessary, to keep it 
from burning and all pipes, wires and gasoline leads pro- 
tected with a covering of asbestos paper. Plenty of room 
should be allowed, so that the welder may have easy access 
to the break, and the frame should be jacked up on both sides 


of the break until the frame is in proper alignment. Then 
weld the crack from the outside, working across the top, 
then down the side and across the bottom, reinforcing a 
little if necessary on all sides but the bottom. Then repeat 
this operation on the inside, reinforcing at all points. Then 
take a strip of steel about one-eighth or one-quarter inch 
thick and six or eight inches long and as wide as the bottom 

FIG. 64. A Good Method of Reinforcing a Weld on an Automobile Frame 
is Here Shown. The Patch as Pictured Here is only " Tacked On." It 
Should be Welded Securely to the Bottom of the Frame on all Four of 
its Edges. 

of the frame. This piece should be welded securely to the 
bottom of the frame with the former break in the middle of 
the strip. A cut representing this job is shown in Fig. 64. 
By this method the frame can be made stronger than origi- 


(97) ASIDE from the difficulties already mentioned in steel 
welding, there are many others. A few of these will be taken 
up in order to let the beginner know how to approach the 
various problems which may confront him. But in no wise 
is this to be considered to be a treatise on advanced work. Oft- 


times the question arises, Can springs be successfully welded? 
Now, while springs have been welded, and they have been 
tested out thoroughly, yet the practice of spring welding 
with the oxy-acetylene flame is not to be recommended. 
There are those who will weld leaf springs, such as are found 
on automobiles, and will apply rapid blows with the hammer, 
while their weld is still in a heated condition and then plunge 
the spring in water or oil to harden it and the weld. A 
close observer will readily see why this procedure is not 
correct. Springs of this nature are made up of metal which 
takes a uniform hardening, and were it not so they could not 
be considered springs. Now, if there is a fracture and a 
foreign metal, which under no circumstances can be expected 
to take the same hardening as the rest of the spring, is intro- 
duced into the weld, it can easily be seen why a fusion of this 
kind is not to be relied upon. If it were possible to diagnose 
or take an analysis of the metal in the spring and use a filler- 
rod which, after being acted upon by the flame, would come 
out the same as the metal in the spring, then some success 
might be expected, but until that time, welding of springs 
will not be encouraged. Unless perchance the break is of 
such a nature that it can be reinforced readily and is in 
such a position that a resilient quality is not necessary. 

(98) Work on crank-shafts often causes perplexity on the 
part of the beginner, for he usually hears this matter discussed 
pro and con. Crank-shafts of four inches in diameter can be 
successfully welded with the oxy-acetylene flame, and even 
larger, if correct methods are employed. There are many 
points which the welder considers before deciding whether a 
weld of this nature is advisable. Of course the usability of 
the piece after it has been welded is the main issue when 
executing any kind of a repair job. Now, a crank-shaft 
will generally break in either of two ways; by some external 
force, such as a connecting rod breaking loose, or by crystalli- 
zation, which is usually due to fatigue. Now, in the latter 


case, ofttimes the shaft will break in the cheek of the ''off- 
set," and possibly no part of the shaft is thrown out of align- 
ment. When such is the case, welding is usually recommended 
and the shaft may be brought back to a useful state in very 
quick order. However, in the former case, the shaft is apt 
to be sprung, and while it could be welded, the machine 
work necessary to restore it to normal requires much time, 
and it has been known, where after spending a matter of 
days in trying to get proper alignments, work was scrapped as 
useless. So it is entirely up to the welder in work of this 

FIG. 65. Building Up Worn Shafts. 

kind to determine whether the job is worth while or not. 
There are certain parts of a crank-shaft upon which welding 
work can be done with a marked degree of success, such 
as building up worn bearings and the like. In doing work 
of this kind it is recommended that the welder fuse his metal 
in a line parallel to the center line of the bearing, seeing to 
it that he has a perfect fusion between the surface of the bear- 
ing and the metal he is fusing and adding plenty of metal, 
to insure enough being used, so that no low spots will show 



up when it is machined. It is considered that by adding the 
metal as suggested the welder will hold his heat much better 
than if he attempted revolving the shaft continually. Fig. 
65 will show the method here outlined in a very clear way. 

(99) When working on shafts the welder will encounter 
such articles as automobile propeller shafts and rear axles, 
which generally break adjoining the square ends. He will 
no doubt wonder whether it is advisable to weld this square 
end back on, or whether to try and build up the shaft the 
desired length. Undoubtedly the point of fracture is the 

FIG. 66. Shaft Broken at End of Square Shank, its Weakest Point. 

FIG. 67. Broken Part of Shaft Removed and New Piece Added, thereby 
Moving the Weld away from the Weak Part. 

weakest portion of the entire shaft, else it would not break 
there. The execution of a weld at this point where no 
additional metal can be added or any means of reinforcing 
used is not to be recommended. Fig. 66 will show the problem 
which confronts the welder, and Fig. 67 the suggested means 
of overcoming the difficulty. By removing about four inches 
from the broken end of the shaft and adding a new piece, 
about ten inches long, of the same diameter, the weld will 
be removed from the weak point; a heavier weld can be 
made, and the end can be machined off to the desired size. 
This procedure is recommended on all jobs of like nature. 


(100) Occasionally case-hardened ring gears are brought 
to the welder to have teeth built up or new ones added, and 
although the welder must realize that the hardening is de- 
stroyed by the action of the flame, yet he does not under- 
stand why it is necessary to reharden the gear. A little 
thought on this subject will make him appreciate the fact that 
if he destroys certain properties in metal which have been 
introduced for a reason, these must be replaced if he would 
bring the job back to normal. It would be like heating up a 
tempered lathe tool, or cold chisel for that matter, and try- 
ing to use it before it had been retempered. Therefore if 

FIG. 68. When Welding a Small Section to a Larger One, the Flame of the 
Torch is Directed toward the Heavier of the Two. 

hardening or temper is destroyed by the flame it must be 

(101) If a weld were to break, it would be necessary for 
the welder to remove all metal added in the first weld before 
attempting to reweld. This is true of his own work as well 
as that of others which he may be called upon to do. For 
no matter how good the surface may appear, without a solid 
foundation no weld is of any value, and unless he clears out 
all of the old metal he cannot be sure of the work. This will 
apply not only to steel work, but to all metals, and it is a point 
which should be borne in mind. 

(102) At times there are jobs come up in which one piece 


of work is to be fused to another which is much larger, and 
will absorb much more heat during the weld. When hand- 
ling such work, it will be necessary to play the torch upon the 
larger piece most of the time, as shown in Fig. 68, in order 
to bring both pieces to a fusion point at the same time and 
keep them in that condition. 

(103) Once in a while it will be necessary for a welder to 
fuse cast iron to steel or vice versa, and the question will arise 
as to which filler-rod he will use. It has been found that 
a cast-iron filler-rod can be used with success and of course 
when using a cast-iron filler-rod, a cast-iron flux will be neces- 
sary. Work of this nature is not very frequent. 


(104) WHEN steel is in a melted condition, it seems to 
be in a very susceptible state. It appears to absorb gases, 
and with constant working an oxidation is in evidence which 
materially effects the strength of the metal.) When working 
o vanadium and other alloyed steels, if kept in a molten 
condition too long, many of their principal characteristics are 
destroyed.! For this reason it is advisable to execute steel 
welds just as rapidly as possible. While this is true of most 
work, it is especially to be emphasized on steel. To assist 
the welder in executing welds on large steel castings, the pieces 
are generally preheated, so that the work will take less time, 
be more successful, and save both oxygen and acetylene. 
When working on preheated jobs, in order to get the desired 
angle on the filler-rod so the welder may use it without dis- 
comfort, a light heat is played on the filler-rod, a matter of 
six or eight inches from the end being fused and then bent 
to an angle of 90 degrees, so that . the operator may hold 
the rod at some distance from his work and still introduce 
it in the manner he desires. Some operators weld their cast- 


iron filler-rods together, to get the desired angle as shown in 
Fig. 69, but this is not as common as the steel method, 
probably because cast iron will not bend and it requires some 
time to weld the rods together in this manner. 

(105) In some parts of the country boiler flues are 
acted upon and eaten away by the impure water used, and 
when high prices prevail, re tipping is generally resorted to. A 
simple method in which they can be satisfactorily and cheaply 

FIG. 69. Kinks for Handling "Filler-rod" on Large Work to Remove Welder's 
Hand away from Heat of Flame. 

(a) shows how the steel "Filler-rod" is heated by the torch flame about 6 inches from the 
end and bent to the angle desired. 

(b) illustrates how cast "Filler-rods" are handled. Since they will not bend, they are welded 
in the T shape shown. First one side is used in fusing, and then the other. 

done is as follows: Cut off the poor end until solid metal 
is reached, with a pipe cutter, which will tend to " V " the 
work as it cuts and at the same time will squeeze the edge of 
the pipe in. After cutting, this end of the flue is placed on 
the horn of an anvil and the burr on the inside, which has been 
made by the cutter, is flattened out. It is very important that 
the flue be of the same size throughout in order to permit 
its being cleaned. It is then placed in " V " blocks or a 


trough, made of angle iron, such as shown in Fig. 70, and the 
new end which has been prepared in much the same way 
is placed in the position shown in A in the same figure. 
The piece is tacked on at two or more spots and then laid 
aside until the whole set of flues has been prepared in this 
manner. Then they are replaced in the trough and welded, 
one after another, being turned at one end by a helper, thus 
allowing the welder to do continuous work. Care must 
be taken at all times that perfect fusion takes place between 
the flue proper and the piece being added, yet at no time 
should the metal be allowed to run on the inside of the pipe. 
More metal can be added than is really necessary and can 


FIG. 70. Showing a Simple Way to "Line-up" Flues when Retipping. 
B Represents the old Flue, and A the New Piece to be Added. 

later be dressed down on a grinding wheel to the desired size, 
which must be such that replacement of the flue can be made. 
Various-sized pipes can be welded in much the same way 
where no reducers are obtainable, the only change being 
that there must be a step made in the trough which will 
permit the various-sized pipes being lined up correctly. 
Jigs for the speeding up of manufactured articles which are 
to be welded are always being brought out by the ingenious 
workman and are to be encouraged whenever possible. 

(106) In the repair of boilers many a feasible job has 



been given up as impossible by the unthinking welder. 
Cracks have been found in fire-box sheets around the stay- 
bolts which, as soon as they are touched with the flame, 
seem to run and keep running. They really discourage those 
who are not familiar with this class of work. Many such 
welds have been executed and are apparently all right until 
tested, when they give way and make the job worse than it 

(Courtesy of the Oxweld Acetylene Co.) 
FIG. 71. Welded Cracks between Staybolts. 

was previously. The trouble is in these instances that the 
welder has made no provision for contraction and while 
the job might appear to be successful, yet the internal strains 
exerted will not show themselves at the test. Many boiler 



shops have found that the flat patch is not to be relied upon 
and when a crack is found between two stay-bolt holes, 
such as shown in Fig. 72, a round hole is cut as shown by the 
dotted line. A circular plate is then cut slightly larger than 
this hole and after being brought to a red heat, it is bellied 
by the use of a hammer or a set of dies, so that it assumes 

FIG. 72. A Crack between the Staybolts in a Boiler should be Cut Out as 
Shown by the Dotted Line, to Prepare it for a "Dished" Patch. 

FIG. 73. A "Dished" Patch. 

the shape of a saucer and is called by many a " dished " 
patch. Some idea may be had of such a patch from Fig. 73. 

(107) The patch is placed in the sheet with the concave 
side toward the operator and should be securely welded in 
place, adding as little metal for reinforcement as possible, 


but seeing to it that a perfect fusion is made between the 
patch and the sheet all the way through. As soon as the 
weld is complete the torch is played upon the high part of the 
patch, which is protruding, and as the weld cools off, sharp 
quick blows can be applied to the center of the patch, which 
should be kept in a heated condition until it is nearly flat. 
This will take care of any contraction that might set up and 
is a very good way of handling patches which do not exceed 
six or eight inches in diameter. 

(108) A " corrugated " patch has been brought out more 
recently than the " dished " patch, and as its name would 

FIG. 74. A "Corrugated" Patch. 

indicate, it has corrugations around at least three of its sides. 
While a " dished " patch is limited in its scope and cannot 
be applied to square holes unless the square holes be cut 
round, the " corrugated " patch knows absolutely no limits 
as to size or shape. While its preparation is probably more 
difficult, yet its purpose is the same, that is, to take care of 
the contraction which takes place in sheets of metal where 
heat has been introduced. To prepare a "corrugated" 
patch, a piece of metal which is somewhat larger than the 
hole is taken and the corrugation is made by placing two rods 
on one side and somewhat separated and between them on the 
other side another rod. With this section of the patch 
heated to a red heat, a drop hammer is played upon it and 


a corrugation effected. Or an easier method is by the use of 
specially prepared dies, which will turn out a patch in quick 
order. It must be remembered that while the patch shown in 
Fig. 74 is only for a very simple job, which is rectangular 
in shape, yet " L " shaped patches can be prepared and 
handled in the same manner. When the corrugation has been 
introduced into the patch, the latter is cut so that it will 
fit the hole, and it is tacked in position with the bellied 
sides out. The method used in applying a patch of this kind 
is to weld the uncorrugated side, then start up the corrugated 
side and weld for two or three inches, then play the torch 
upon the corrugation, adjoining the part welded, and slightly 
hammer to assist in the expansion of the same; then return 
to the weld, continuing it until the corrugation can again be 
played upon. By doing this, when finished the patch will 
be flat and no signs of the corrugations will be shown. While 
many patches of this nature are in use giving the very best 
service, the welder who looks upon the finished job cannot 
tell how it has been accomplished. 

(109) While the methods here given seem only to apply 
to boiler work, they are not so restricted and can be applied 
to tanks and various vessels with success. However, when 
welding on tanks which have contained inflammable gases or 
gasoline the welder is cautioned to take every measure to 
safeguard himself, and while it is known that much work is 
being done on such jobs, it is not recommended and in fact 
quite the contrary. It is true that there are such methods as 
filling the containers with water; cleansing with live steam, 
and so forth, but the cautious man will refrain from working 
on these vessels even though such measures have been 
taken. Gasoline has a faculty of penetrating the pores 
of metallic surfaces, and although these vessels have been 
emptied and have remained so a matter of a year, the gaso- 
line is still present to some extent, as is evidenced by the 


fact that as soon as heat is applied and the molecules of the 
metal are expanded, the gas is released in sufficient quantities 
to cause an explosion. This is not in one instance only, 
but in many, so it has been thought best to discourage any 
welding work on vessels which have contained gasoline at 
any time. 

(no) While it is possible to weld cast iron on the vertical, 
by the use of carbon blocks and so forth, the same kind of 
work can be accomplished on steel with much ease, without 
the use of any blocks, or materials other than the filler-rod 

FIG. 75. Working a Vertical Weld on Steel, from the Top Down. 

and the welding torch. There are two methods of handling 
vertical welds; welding from the top down, or starting from 
the bottom and working up. The former seems to be con- 
demned by those who have never tried it, on account of the 
carelessness which is apt to be used on work of this kind. How- 
ever, for the beginner, it is thought advisable to teach this 
method, as there are many places where it can be used ad- 
vantageously. The metal at the top of the seam, such as a 
broken automobile frame, or the like, is brought to a molten 
state and held there, not only by the velocity of the flame, 
but also by the filler-rod, as is shown in Fig. 75. With the 


choosing of a tip of the correct size, the melted metal can 
be held under control with much ease, after a little practice, 
and it is allowed to descend as soon as the metal below it 
is in the proper shape for fusion. The filler-rod is added 
continually, for it is never lifted out of the molten metal, 
merely stirred a little from side to side as it descends. None 
of the melted metal is allowed to precede the flame, and at all 
times the operator can see whether the edges to be fused are 
at the right heat. As soon as the bottom is reached, the weld 
can again be gone over if it is not thought strong enough, 
and reiniorced as much as desired. As soon as the operator 
is familiar with this method, he will find that much more 
speed can be developed, less filler-rod lost and less lapping 
done than by building up from the bottom. 

(in) In welding over head there is a tendency on the 
part of most welders to avoid the use of enough heat to bring 
their metal to a molten state, for fear that it will drop upon 
them. It must be remembered thai lack of heat means poor 
welds and that the metal must be in a molten condition when- 
ever the weld is to be made. As soon as a little practice is 
given to this kind of work, the welder will see that the melted 
metal can assume some proportions without dropping off, 
despite its weight. It has probably been noticed that on 
" sweating " water tanks drops of water accumulate on the 
bottom of the tank and do not fall off. It is the same sort 
of problem in the case of melted steel. The adhesion of the 
molecules and the surface tension are the forces that keep the 
metal from dropping. 


(112) IT is difficult for the beginner to accustom him- 
self to brass welding, especially on large work. While he 
has been taught to believe that brass has a much lower 
melting-point than iron or steel, yet when he comes face to 
face with the actual problem of melting it, he will find that 
it is necessary to hold his flame in contact with his piece much 
longer, on brass work than on either of the other two, before 
the melting point is reached. This can be accounted for by 
the great conductivity of brass. On cast iron and steel 
the heat was rather local, but on brass work it is transmitted 
to all parts of the piece as rapidly as it is introduced, and this 
absorbing process continues until practically the entire piece 
is near the melting point. 

(113) Brass has for its base, copper to which an alloy 
of zinc has been added. Now the most difficult part of fusing 
brass work, is to add more metal from the filler-rod to the 
parts which are to be fused, without burning up any more 
of the alloy, than is absolutely necessary. Seeing that the 
copper and zinc have different melting points, it is a very 
difficult feat and requires considerable practice. Much of 
this trouble can be eliminated by the use of a filler-rod which 
has the correct proportion of alloy added, so that it may take 
care of and replace any that has been destroyed by the flame. 

(114) Brass work is " V-ed " out when welding is to be 
done, in practically the same way as cast iron. Only under 
no circumstances should the ends of the parts be burned 



off, when " V-ing," as the heavy oxide which is deposited 
on the remaining metal is very hard to combat with the weld- 
ing flame. The ends of the work are brought to a red heat 
with the flame that is slightly carbonizing. This is held 
directly in contact with the work during the preheating 
stages, in much the same manner as on cast iron, and a small 
layer of carbon may be seen to accumulate around the weld. 
Now, in theory, this would seem the worst thing possible to 
have present, but in practice a small quantity of this soot 
acts as an aid in making the weld, besides making the flame 
less intense, which saves much of the alloy, from being 
burned when the fusion occurs. When the ends have become 
red hot, the same procedure is used as in working steel, 
except that the torch is given a slightly greater angle and a 
brass flux is used. 

(115) Contrary to most authorities we find that an 
abundance of good flux is desirable on brass work and that 
it is almost impossible to use too much. It is desirable 
to use only the best welding fluxes, for the best welds are 
to be insured only under ideal conditions. If a welder were 
to run short of flux, however, he might use powdered borax 
of the 20 Mule Team variety, to tide him over until he could 
get a new supply. The flux is added in the same way as the 
cast-iron flux, that is, by dipping the heated end of the filler- 
rod into the flux container. Enough will adhere, and when 
added will clear up the metal in the vicinity of the weld. It 
should be added as often as a welder notices his metal needs 
cleaning and this will vary depending upon whether there is a 
slow or rapid worker behind the torch. A man must use 
his own judgment in cases of this kind. Remember that 
the flux is a cleaning agent and if the surface is clean, no 
additional flux is necessary, but if the contrary is true, that 
is, if the surface is full of oxide and the filler refuses to flow 
easily, flux is necessary and should be added. 


(116) During the welding, dense white fumes will come 
from the fusing brass. This is the burning out of the alloy, 
that is, the zinc. These fumes are injurious to the welder and 
should be avoided, if possible, by proper ventilation. The 
use of a proper filler-rod and rapid work will largely tend to 
overcome the presence of these fumes, but if the operator 
is very slow, they will appear, and are followed by a porous 
and brittle weld, which if broken afterwards will show a 
large number of blow holes. The most difficult part of brass 
welding as a whole is to add the filler-rod, being certain of a 
fusion, without burning out the zinc. When brass is in a 
heated condition, it is very fragile and will crack readily 
if disturbed. All precautions should be taken to see that no 
sudden jarring is given the piece until the weld has completely 
set. When this work is done many welders plunge their work 
in water, in an effort to make it more ductile and easier to 
machine. While this, of course, is condemned by theorists 
and rightly so, in practice there seems to be no injury results. 


(117) So far as the actual fusion of aluminum is con- 
cerned, it is probably more easily learned than any other 
metal, but on account of. the rapid conductivity of heat and 
the loss of most of its strength when heated, aluminum has 
caused much concern among oxy-acetylene welders. 

(118) There are two methods used in welding aluminum, 
the flux method and the puddle method. The puddle 
system gets its name from the use of a puddle stick or spoon- 
like rod which is used to stir the metal together, and is very 
satisfactorily used on all cast aluminum. The flux method is 
applied to both cast and sheet aluminum and it is so-called 
because a flux is used to break up the oxide along the line 
of weld. The discussion to follow applies only to cast 
aluminum. It is in this metal that most interest is centered, 
as the welding of sheet aluminum, such as is found in auto- 
mobile bodies and some cooking utensils, is not encountered 
in the ordinary run of work. 

(119) When working with the flux method about the same 
sized tip is used as when working on cast iron. This is applied 
to the line of weld and held there until the oxide on the sur- 
face commences to wrinkle and small globules of a mercury- 
like appearance form on the surface. When heat is intro- 
duced in aluminum it is transmitted throughout the piece 
in the. same manner as occurs in copper and brass, therefore 
it will require much more time to heat the work than the same 
sized piece of cast iron or steel. As soon as the weld assumes 






the condition mentioned, fast work is necessary or the metal 
will collapse, for it loses most of its strength when heated to 
this condition. The end of the filler-rod bearing the flux 
is brought down on the metal and immediately the surfaces 
will clear up and run together, like so much mercury. The 
torch is instantly jerked away and applied farther along the 
weld. The theory of this reaction is that the heavy alumi- 
num oxide is the only thing which prevents the metal flowing 
together when heated, and as soon as the flux is introduced 
this oxide will be destroyed along the line of weld and a fusion 
of the metal effected. This actually takes place, providing 
enough heat has been introduced to permit this reaction to 
penetrate the depth of the weld. The flux contains the 
chemicals necessary to cause this reaction if the metal is 
in the right condition. There are many welders who do not 
use sufficient heat and blame the faulty results upon the 
flux. On the other hand, there are many fluxes which are 
absolutely useless in performing a function of this kind. 
The chemicals necessary in compounding a good flux for 
this class of work are expensive and therefore this flux cannot 
be procured at a low price. When the weld is finished and 
cooled the surface should be scrubbed with soap and water 
to remove all traces of the flux, otherwise a corrosion may 
occur a month or so afterwards, and while it may not affect 
the weld in any degree, the owner of the piece may not be 
pleased at the sight. It is therefore advisable to remove all 
traces of flux used on aluminum work. 

(120) The puddle system differs from that of the flux, 
insomuch that when the metal has been brought to the 
same heat, where the flux has been applied it will be found 
that the metal is really in a pasty condition. It can be 
stirred together and the break entirely eliminated by the use 
of a puddle stick, either of a pointed or a flat spoon-shape 
design, as shown in Fig. 77. During this puddling stage, 


the torch is usually held in the left hand with the flame some 
distance away from the work, only introducing enough heat 
to keep the puddle pasty. The puddle stick is handled 
by the right hand and when extra metal is needed the puddle 
stick is laid aside and the aluminum filler-rod is picked up 
and worked into the weld. When sufficient metal has been 
added the puddle stick again comes into play and can be 
used in stirring the metal together and finishing it off in the 
desired manner. Reinforcing the weld will apply to aluminum 
the same as every other metal, and a very neat job can be 
made after a little practice with the puddle stick. At times 

FIG. 77. "Puddle-sticks" for Welding Aluminum. 

some of the aluminum may adhere to the stick, which is made 
from a quarter-inch piece of steel filler-rod, but this can be 
removed by scraping it upon the fire bricks which should be 
in the vicinity of the weld. 

(121) There are two kinds of filler-rods used in aluminum 
welding. Both are aluminum, but one is cast and the other 
is 9 drawn rod. This same difference will also be noticed in 
bronze filler-rods, and there has been much discussion as to 
which is the desirable one to use. Neither of them is sup- 
posed to be 100 per cent pure aluminum, as such a filler-rod 
does not give the desired results under the action of the 


flame. A matter of from 90 to 95 per cent aluminum, with 
5 per cent to 10 per cent of copper present as an alloy, is found 
to make a stronger and more successful weld. It is recom- 
mended, if possible, to use the drawn rods whenever avail- 
able; for a weld at best is only a casting, and if this casting 
can be made from virgin metal, rather than recast from metal 
which has been cast many times and the contents not known, 
it is thought that the results will be far more satisfactory. 
A weld made with such a filler-rod, care being taken to work 
out the oxides, will compare very favorably with the strength 
of the original metal and in many instances a reinforcement 
will make it much stronger. 

(122) To combine the two methods of welding aluminum 
is not recommended. If the flux were stirred up inside the 
weld with a puddle stick an unsatisfactory weld would result, 
so they are to be kept entirely separate. It is not necessary 
to " V " out aluminum for the same reason as other metals 
are " V-ed " out. When it is in workable condition it can be 
puddled and stirred about as desired. It is well, however, 
to " V" out slightly for the sake of marking the line of weld. 
When aluminum is heated up, the expansion which occurs 
may close up the crack, which was previously quite visible, 
in such a manner that it cannot be located without much 
loss of time. Ordinary chalk or soapstone, if available, 
may be used to mark any preheated work, but the use of a 
chisel along the line of weld is the most reliable method. 


(123) IT will be noticed, when welding aluminum, that 
bright surfaces will oxidize immediately when exposed to the 
air. This action occurs perhaps faster on aluminum than on 
any other metal. With this oxide or scale present the metal 
will not run together nor fuse, no matter how much heat is 


applied. The metal may be molten on each side of an 
oxidized crack and at times will cause the line of fracture to 
even float, but if the oxide is not destroyed the metal will 
not fuse. As has been noted previously, two methods are 
used to destroy this oxide, namely, the flux method and the 
puddle system. On account of this exceedingly rapid oxida- 
tion, it will be found to the operator's advantage to complete 
his aluminum welds as quickly as possible in order that he 
will have less of this oxide to combat. It will be found in 
using the puddle system that greater haste can be made by 
using the torch in the left hand, leaving the right free to do 
the puddling and to add whatever metal is necessary. In 
this method most of the success depends upon the operator's 
skill in handling his puddle stick and puddling in additional 
metal. Generally the right hand can do this more rapidly 
than the left. 

(124) It is well to learn how to make a successful weld 
from one side of the metal only, and while this will apply 
to all metals, it is especially advantageous in working 
aluminum. Where a small layer of metal has been added 
to one side of an aluminum job, such as a crank case, and it 
does not penetrate the entire thickness of the metal, when the 
other side is turned, and the flame applied to it, a difference 
in temperature and the loss of strength in this metal when 
heated will cause the first side welded to crack unless the 
operator is extremely cautious. Therefore it is always well 
to learn how to penetrate the entire thickness of the metal 
from one side and make a satisfactory weld in this manner. 

(125) As previously stated, aluminum when melted 
loses most of its strength, and if not supported by some 
means or other the metal will collapse. On account of this 
it is advisable to back up aluminum work, when possible, 
whether the job is to be done cold or in preheated condition. 
The most successful manner of backing up is shown in Fig. 



78, wherein A represents a thin sheet of copper which has 
been fitted to the work, and daubs of asbestos cement shown 
at B will aid to some extent in holding the plate in position, 
but this alone should not be depended upon. A prop or 
fire brick, upon the top of which has been placed a cushion 
of cement, will serve as a good backing, but where this cannot 
be accomplished filler-rods may be bent in the manner shown 
in Fig. 78. These filler-rods are not of the springy type, 
but are of soft wire and the loop as shown is not for a spring 

FIG. 78. One Method Used to " Back Up " Aluminum Work, when Welding. 
A Represents a Sheet of Copper; B, Asbestos Cement. 

effect, but merely to take care of the contraction and expan- 
sion of the wire. Copper is given a preference over most of 
the other sheet metals, because it can be peened with a hammer 
to any shape desired, and many odd shaped additions can 
be formed by its use. 

(126) The use of clamps, when working on aluminum, is 
not recommended on account of the great conductivity of 
heat and the weakening of the metal as it approaches the 
melting-point. Pressure of any kind is not desired and the 


operators who attempt to use clamps will regret it sooner or 

(127) In aluminum work contraction and expansion take 
place the same as in other metals, only to a much greater 
extent, and greater allowances must be made. However, 
the same rules can be applied when determining whether 
work should be preheated or not, for if the ends are free to 
move, the work can usually be accomplished without pre- 
heating, whereas if confined, it will be necessary. When 
preheating is necessary the whole piece must be treated in the 
same way, regardless of the size. If only part of the work 
were preheated and the balance left exposed, it would be almost 
impossible to avoid warpage and shrinkage strains, which 
would render the work useless. Always preheat the entire 
piece if any portion requires it. 

(128) Great care must be exercised when setting up alumi- 
num work for preheating. Its weight should be distributed 
equally on whatever support is used, so that there will be no 
danger of any one part sagging, thereby throwing the whole 
piece out of alignment. A good way of accomplishing this 
is to lay fire bricks on their flat side, in such a manner that the 
weight of the work will be fairly well distributed. Then put 
a daub of clay or asbestos cement on each brick and press the 
aluminum piece down on this cushion. This will overcome 
the use of shims and other methods used for jacking up the 
work, which are unreliable. 

(129) If charcoal is to be used as a preheating fuel, an 
oven of fire brick should be built up with draft holes in the 
bottom layer of brick, as described in the chapter on Pre- 
heating. A layer or two of charcoal is then ignited. The 
oven is then covered with asbestos paper or a piece of sheet 
metal. Asbestos paper is preferable as the metal becomes 
very hot and is apt to burn the operator. After the fire 
has received a good start, additional charcoal is added 


until sufficient heat is obtained. This can be determined by 
sprinkling a little sawdust on the surface of the aluminum, 
and if it chars readily, the work is ready to weld, Other 
methods have been outlined previously, any or all of which 
may be used in learning this heat. In executing the weld 
as little of the work is exposed to the air as possible, in order 
to hold a uniform heat and not permit any part to become 
chilled. At the completion of the weld the oven is covered 
over, the openings in the bottom row of bricks are stopped 
up, and the piece allowed to cool with the dying fire. The 
charcoal process is the slow but sure method of handling 
preheated aluminum work, and is always recommended. 

(130) When preheating aluminum with torches burning 
kerosene or gas a different kind of oven is built, as previously 
described in the lecture on Preheating. No openings are left 
in the lower row of bricks and the oven is built very much 
closer to the work being preheated. As the object is to con- 
fine as much heat as possible and have a uniform tempera- 
ture throughout, it is not desirable to have such ovens loosely 
constructed. If the bricks are irregular, a double wall can 
be built with a layer of asbestos between them. Such a pro- 
cedure is always recommended if time and bricks permit. 
A hole is left in one end of the oven for the preheating torch 
flame to enter. On aluminum work the flame is never played 
directly upon the metal. A baffling plate of metal or fire 
brick is used to distribute the flame around the sides of the 
piece and very satisfactory results may be obtained by 
preheating in this manner. 



(131) MANY times aluminum crank cases which have large 
holes punched in them and parts missing are brought to a 
welder for repairs. A question arises as to whether it is best 
to back up these holes and fill in the missing parts with a 
filler-rod as the welding progresses, or whether these parts 
should be cast separately or cut out of another crank case. 
It will generally depend upon the size of the hole, as to the 
desirable procedure in a case of this kind. It must be re- 
membered that if the casting and welding are to be done at 
one and the same time each additional layer of metal 
must be fused to the last layer and that in reality a great deal 
of welding is necessary. In addition this added metal must 
be fused to the crank case. On small holes, perhaps two or 
three inches in diameter, this method is recommended, but 
if the hole is much larger, it is best to cast a piece and then 
weld it in, for in this instance there is only one line of weld 
to look after. 

(132) On aluminum work it is proper to weld from the 
closed end of a crack toward the open, whether the piece has 
or has not been preheated. This is true also of all other 
metals, for if the weld were to be started at the open end and 
worked backwards there would certainly be internal strains 
set up, which would be undesirable. If it is not clear which 
end is the open one, the operator should stop a moment and 
figure it out. 

(133) Were a suspension arm of the U type on an 
aluminum crank case to break about three or four inches from 
the body of the case, it could be welded in place without dis- 
mantling the motor, if handled properly. Free access must 
be had to the line of break, so that the operator can manipu- 
late his flame at whatever angle he thinks best. Due to the 
contraction and expansion, which may throw the piece being 


welded out of alignment slightly, it is best to blank the 
bolt hole at the end of this suspension arm and face it off, 
before the piece is welded in position. Later a new hole can 
be drilled which will line up accurately with the frame, and 
the welder will not then have to worry or attempt to return 
it exactly to its former position. In order to keep the case 
itself as cool as possible, wet asbestos should be packed 
around it, near the broken arm, so that too much heat will 
not be absorbed by it. The broken end is then tacked in 
position at two or three places and the weld started. On 
such a problem the puddle system will be found best, for both 
horizontal and vertical welding are to be done, as well as some 
overhead. As flux causes the metal to flow, it is rather 
difficult for the beginner to apply it to vertical and over- 
head work. The puddle stick should work through the metal 
its full thickness and eliminate every possible trace of the 
break, digging out the old metal where dirt is found, and adding 
new metal for reinforcing. When one side has been welded 
and reinforced it should not be allowed to cool while the other 
side is being worked. The torch should be played upon it 
every now and then, in order that the whole line of weld will 
be at approximately the same temperature; otherwise, the 
weld may break in cooling. The ease with which aluminum 
is puddled together, which many welders have likened to the 
children's method of making mud pies, seems so simple to the 
beginner that he cannot see where the strength comes from 
when cooled. On account of this, he invariably works his 
aluminum too long. After welding a few test .bars of this 
metal and breaking them in the line of weld, many old welders 
will gain confidence upon seeing the results of their own 


(134) THE welding of malleable iron, so far as the actual 
fusion of the metal is concerned, is not practiced except in 
very few instances, where the parts are very thin and have 
been completely annealed. This is on account of its being 
what might be termed a heat-treated metal. To begin with, 
malleable iron is cast iron, and becomes malleable only after 

FIG. 79. Illustrating Cross-section of Malleable Iron. 

it has been heated to the proper condition in the presence of 
material which will absorb much of its carbon content, and 
kept in this state until a suitable depth of its exterior has 
been annealed. It has been changed from a brittle casting 
to one which will bend to some extent without breaking, and 
its surface, by the withdrawal of the carbon, has been con- 
verted into steel. The interior remains cast iron. The 
depth of penetration will depend entirely upon the number 



of hours the work is treated. Usually it runs from one- 
sixty-fourth to one-eighth of an inch, depending upon the 
type of work. An idea may be gained of how a cross-section 
of this metal will appear, by noting Fig. 79. 

(135) A machinist would not think of destroying the tem- 
per in his tools and then attempting to use them without 
retempering them. So the welder will not attempt to melt 
malleable iron, for he realizes that if he were to attempt fus- 
ing this metal that its character would be entirely destroyed. 
If he should make a fusion, the weld itself and in the vicinity 
thereof the metal would be very brittle and retain none of 
its ductile qualities. When- a weld of this kind is attempted, 
first, a few steel sparks are given off from the surface of the 
metal, which quickly diminish and the surface seems to recede 
from the flame. A white foam appears as the steel surface 
is burned and many small blow holes then make their appear- 
ance. The casting resembles a steel casting which con- 
tains much sand and impurities. The welding of malleable 
iron, in its broadest sense, is therefore not recommended, 
although as it has been stated there are occasions when it 
can be successfully accomplished. The best manner of bond- 
ing malleable iron is by the use of a bronze filler-rod, and 
this process will hereafter be referred to, for convenience, 
as welding, although it may resemble brazing in some 

(136) The art of welding malleable iron with bronze is 
not very difficult to learn. Possibly, the greatest trouble will 
be experienced by the beginner in distinguishing malleable 
iron from other castings. By again referring to Fig. 43 and 
carefully noting the various methods outlined, this trouble 
should be overcome. Many times, too, if the welder has 
had any mechanical experience, he can probably determine 
where the casting has been used and can ofttimes satisfy 
himself whether it is malleable or not. Malleable castings 


are very seldom used as a wearing surface, and are generally 
employed where there is strain, to replace steel castings and 
forgings, which are much more expensive. If it has been 
determined that the metal is malleable iron, half the battle 
has been won. 

(137) In preparing malleable iron, a clean surface is 
necessary in the vicinity of the weld. No " V-ing " out is 
necessary unless the piece is greater than one-quarter inch 
in thickness, and then the surface of the " V " should be as 
rough as possible. The ends are placed as close together as 
possible, the same as in brazing, and a welding tip which is 
one size smaller than would be used on the same thickness 
of cast iron is then used, with a slightly carbonizing flame. 
See Fig. 23. The work is heated, the same as in cast iron 
and steel. This flame is played directly on the work in a 
vertical position, similar to that used in preheating the weld 
in cast iron and steel, until heated to a cherry red, back about 
one-half inch on each side of the weld. As soon as this heat 
is obtained, the bronze filler-rod carries a quantity of bronze 
flux to the weld and this further tends to clean the surface. 
With the end of the filler-rod directly in contact with the 
work nearest the operator, the neutral flame melts the end 
of the rod, which immediately should run over the adjoining 
surface and through the crack. When this occurs the flame 
is abruptly twisted away from that portion of the weld to 
avoid burning the bronze. This is repeated along the line 
of the weld until the entire surface is covered with a thin 
coating of bronze. With this as a foundation more bronze 
is added, but during this process the torch is turned so that 
the neutral flame will not bear down directly on the bronze, 
which has already been added. It should rather strike it at 
an angle and radiate enough heat from the side of the neutral 
flame to permit a fusion between the filler-rod and the bronze 
already added. Much more surface should be covered and 


more of a reinforcement made than in either cast iron or 
steel, in order to warrant enough strength for this class of 

(138) A good bronze for welding purposes should work 
easily under the influence of the oxy-acetylene flame and 
have sufficient alloys present to take care of those destroyed 
by the action of the flame. It is not thought advisable to 
work over welds of bronze, for fear of making them porous, 
unless more filler-rod is added whenever the flame is brought 
in contact with the weld. 

(139) Welds of malleable iron can be made which will 
be even stronger than the surrounding metal, and at times 
they can be reinforced by adding small strips of steel. These 
can be entirely covered, to make them inconspicuous. Con- 
trary to custom it is recommended that plenty of flux be used, 
for best results have been found when a surplus rather than 
a sparing amount has been employed. 

(140) The matter of heat in malleable iron is of con- 
siderable importance. If not enough heat is used there will 
be no fusion between the bronze and the iron, whereas on 
the other hand, if too much heat is used, the bronze will not 
adhere, but will seem to boil on the surface and form in small 
globules rather than spread over the whole metal. In addi- 
tion the character of the piece being worked on will be changed 
when heated too much. This matter of heat should be given 
great attention and the beginner should learn and have em- 
phasized the fact that the proper heat is one which will per- 
mit the bronze to run like water over the surface, and this 
will form a good foundation to work upon. 

(141) In general, malleable iron work is seldom preheated, 
for this is not necessary if the pieces have been fitted together 
as closely as possible before the weld is started. Once the 
student has learned the flow of metal and how to reinforce 
his weld, he will be in a position to handle most any kind of 


malleable iron properly. It is well to remember, however, 
that malleable iron is allowed to cool slowly and is not 
immersed in water, as has been suggested when working on 
brass, for here we have one metal in the piece itself and 
another in the weld, and too great a strain would set up if 
they were cooled abruptly. 


(142) BY heating a bar of wrought iron or steel to a 
welding heat and holding it in a stream of compressed air, 
or a strong blast, it will at once begin to melt and sizzle, 
emitting an incandescent and scintillating light. This light 
is dangerous to observe at close range without colored glasses. 
The burning of the metal can be maintained for hours, without 
any other source of heat except that caused by the combus- 
tion of the iron. The oxy-acetylene cutting process is based 
upon this principle, in that a neutral flame is applied in order 
to heat the part being cut to the desired temperature. Once 
the melting-point is reached, pure oxygen under pressure is 
applied to maintain oxidation and force out the burned 

(143) The apparatus used for cutting does not differ 
to any great extent from that of the welding class, except that 
a different torch is employed. There are combination 
regulators and torches manufactured, but a combination tool 
is always regarded by most authorities as a loss in efficiency, 
either on one side or another. While a low-pressure welding 
regulator may be used on the oxygen line for cutting, yet its 
use upon large work, where the pressure is high and the regu- 
lator must pass a great deal of gas very freely without freezing 
up, this low-pressure regulator will be a serious handicap and 
cause much trouble, if used. 

(144) An ideal arrangement on the oxygen line for cutting 
is to have a double or " twin " regulator attached to the oxygen 




drum, one side of which will do for welding and the other, 
being high-pressure type, will produce a constant flow of 
high-pressure gas, suitable for the cutting jet. Then when 
cutting is done a three-hose torch should be employed. One 
of its oxygen connections which governs the neutral flame 
can be connected to the low-pressure regulator, while the 

FIG. 80. The Cutting Torch Eats its Way through Steel of any Size with 
Remarkable Ease, Leaving a Clean-cut Edge. This View Shows a Cutting 
Torch in Operation at the Ordnance Welding School, U. S. Army. 

oxygen jet should be controlled by the high-pressure regulator, 
the third connection will furnish the acetylene gas for the 
preheating flame. However, in place of this three-hose 
arrangement, most cutting is accomplished by means of a 
two-hose apparatus, wherein only one hose is used to convey 
the oxygen from a single regulator to the torch. On such 


apparatus much trouble is usually experienced in cutting 
old metals where a great deal of scale is present or in a close 
place where the torch is apt to get hot. 

(145) Many times part of the scale or metal will pop 
up against the tip and cause the oxygen jet to flicker. This 
slight variation may cause an excessive pressure of oxygen 
to be introduced into the preheating flame momentarily, 
by backing up the oxygen in the cutting jet. This lean 
mixture of gas will generally flash back instantaneously and 
will deposit a layer of carbon on the inside of the tip, which 
causes much annoyance to the operator. This condition is 
to be found where there is but one oxygen line. In the two- 
hose arrangement this is entirely overcome, due to the 
independence of the pressure on each line. 

(146) The high-pressure regulator differs from the low- 
pressure regulator in these respects: The diaphragm, see 
Fig. 1 6, is much smaller in diameter, which makes it less 
sensitive, and of course much stronger. The diaphragm 
springs are usually much heavier; the nozzle contains a 
larger opening for passing gas freely without freezing; and 
to take care of the increased pressure on the line, usually a 
higher pressure working gauge is added to the regulator. 
Such a regulator is capable of passing much more gas than 
the low-pressure type, but as far as being as sensitive and 
maintaining a constant, absolute flow of gas, its design will 
not permit it to do so. In cutting, these requisites are not 
necessary. In welding, however, the delicate adjustment of 
the flame demands a very sensitive regulator and usually 
the larger the diameter of the diaphragm the more sensi- 
tive the adjustment. 

(147) The cutting torch differs from the welding torch 
in many respects. The tip itself, when looking at its end, 
may resemble any one of the views shown in Fig. 81. In 
the welding torch, but one hole is to be found in the tip; 


in the cutting tips, two or more holes are to be found. In 
all cases the center hole passes pure oxygen, whereas in the 
surrounding holes, both oxygen and acetylene mix and when 
lighted give a neutral flame. This will hereafter be called 
the preheating flame. The gases issuing from these openings 
are controlled by three valves, one of which may have a 
trigger or lever arrangement for quick action, and it will 
control the center jet of oxygen which really does the cutting. 
This is under much higher pressure than the preheating 
flame. The other two valves will control the oxygen and 

FIG. 81. End Views of Cutting Tips, Showing Possible Arrangements of 
Preheating Flames in Regard to Oxygen Jet. The Black Circles Repre- 
sent the Preheating Flames, which Vary in Number and Arrangement 
According to the Nature of the Work, the Possible Limit being a Con- 
tinuous Circle, as Shown. The White Circles Illustrates the Oxygen 
Jet, which, too, Varies in Size According to the Work. 

acetylene gases used for the preheating flame. In lighting 
such a torch, the acetylene is turned on in the same manner 
as has been taught when welding, until it just leaves the end of 
the tip. Then the oxygen valve is opened, which controls 
the preheating flame, and enough is permitted to pass to 
produce a neutral flame. As soon as this has been accom- 
plished, the third valve should be quickly opened and held 
so a moment, to see if the neutral flame has been changed. 
Generally this operation will deprive the neutral flame of 
some of its oxygen, and a feather flame, showing too much 



acetylene and not enough oxygen gas, can be noticed. This 
will necessitate turning on slightly more oxygen at the torch 
valve. The third valve is then shut off and the torch is ready 
to start cutting. 

(148) On small cutting jobs, about as much acetylene 

(Courtesy of the General Welding & Equipment Co.) 

FIG. 82. Cutting a Heavy Shaft. 

pressure is used on the line as there would be if it were a 
welding job. The oxygen pressure, however, is generally 
much greater, and a pressure anywhere from ten to two 


hundred pounds should be used, depending upon the thick- 
ness of the metal and the conditions which must be met. 
In extreme cases where very heavy cuts are to be made, a 
much higher pressure than has been mentioned should be 
used, but the limitations given will cover a wide range of 
work. To start a cut it is necessary to bring the preheating 
flame in contact with one edge of the metal to be cut and play 
it there until the metal is red hot. As soon as this condition 
is reached the torch is held steady the neutral flame 
just touching the metal; then the third valve controlling 
the cutting jet of oxygen is opened. This oxygen, under high 

FIG. 83. Position to Hold Torch in when Cutting Metal. 

pressure, quickly acts upon the hot metal and severs it instan- 
taneously, melting and oxidizing the metal so that it will not 
flow together, in one and the same operation. As soon as 
this occurs the torch should be advanced as rapidly as possible 
in the direction the metal is to be cut. The more rapid the 
advancement and the steadier the torch is held the cleaner 
the cut will be; and incidentally, less gas consumed in the 
execution of the job. In cutting, as in welding, it is always 
well to give the torch a chance, and when the operator sees 
much molten metal splashing directly back on the torch, he 
should change the angle slightly to avoid his apparatus 
becoming overheated. It has been found that if the cutting 


torch is held at the angle shown in Fig. 83, the most satisfac- 
tory results can be expected. 

(149) At the present time only such metals as steel and 
wrought iron can be successfully cut. When it comes to 
cast iron no method has yet been discovered to cut it with 
any degree of success by the oxy-acetylene flame, on account 
of the high melting-point of the oxide and various other mat- 
ters. The day is looked forward to, however, when after 
sufficient time and study has been devoted to this subject, 

FIG. 84. Method of Cutting with Two Welding Torches. Torch A is Adjusted 
so that a Neutral Flame will do the Preheating, while a Fork in the Oxygen 
Line Supplies Oxygen only to Torch B, and it does the Cutting. 

that cast iron can be as successfully cut as any other metal, 
by introducing another gas or agent to destroy some of 
the reactions which retard its application at the present 

(150) The use of the cutting torch in preparing steel 
work, for welding of large size, plays an important part, in 
quickly and efficiently " V-ing" out and getting it ready for 
use. Care should be taken, after its use, to see that the 
heavy oxide which it leaves is largely destroyed, before any 
more metal is added. 


(151) Frequently the welder has a call for a cutting 
torch, where none is available, yet an extra welding torch 
or two may be on hand. If this is the case, two welding 
torches may be fastened together in such a manner that a 
temporary job of cutting may be handled. The arrange- 
ment shown in Fig. 84 illustrates this point. If no extra 
welding torch is available, a carbon burning torch or any piece 
of copper tubing which has a valve in one end, suitable for 
taking a hose connection, and the other end free to have a 
welding tip brazed on, can be used in the same manner. The 
welding torch will give the neutral flame and the extra line 
of oxygen will do the cutting. It is well to remember that 

FIG. 85. When no Edge is Available to Start the Cut on Large Work, Much 
Time may be Saved by Making a Curl with a Cold Chisel, as Shown. 

oxygen, no matter under what pressure, cannot be expected 
to act upon cold metal. A red heat is absolutely necessary. 
There are various short cuts, it is true, in obtaining this heat, 
and where a large shaft is to be cut, the operator would not 
think of playing his torch upon such a piece of metal until 
it was red hot in the locality in which he wished to start 
his cut. This would consume too much time and gas. Gen- 
erally a hammer and cold chisel are brought into play and a 
slight curl on the metal is obtained as shown in Fig. 85. 
The moment this becomes red hot, the oxygen jet may be 
turned on, and the cut commenced. As soon as started, the 
operator is able to " carry-on " at will, 


(152) An armored hose is generally used on the oxygen 
line for cutting, as well as on the acetylene line, as there is 
much more pressure used in cutting than in welding. This 
type of hose wears much longer and does not kink to the extent 
that the unprotected hose does. The armor protects both 
lines from being burned by the melted metal, which is very 
apt to come in contact with the rubber, were it not protected' 
in some manner. 

(153) The question often arises in welding circles, as 
to why, since the cutting torch contains a series of neutral 
flames, it would not be just as well to use such a method in 
welding, as no doubt more heat could be obtained and a greater 
surface handled. The answer to such a question would be, 
that the opportunity for oxidation is so great that successful 
welding could not be expected, although if this were the last 
means at a welder's disposal, he would certainly be justified 
in making a weld in this manner. He should be very careful, 
however, to see that his extra oxygen supply is completely 
shut off and that there is no possible chance for that gas 
leaking into the weld. 

(154) To plunge a flame, such as is used in the cutting 
torch, under water and see it continue to burn while sub- 
merged, looks quite marvelous to the average layman. Yet in 
cutting piling along water fronts this is continually being done. 
Not only does the torch stay lighted, but it retains much 
of its efficiency as a cutting tool, and some instances have been 
recorded where cutting has been accomplished at a depth of 
thirty feet under the sea. It is true that the water conducts 
a large part of the heat away very rapidly, but to facilitate 
such operations, an air line is brought down which ejects 
air under the torch and clears the water away to some extent, 
but this is not necessary. In order to explain this phenomenon 
in a very simple way, it will be stated that nothing will burn 
unless oxygen is present, and the more oxygen used, up to a 


certain point, the more rapidly will the burning take place. 
When submerging the cutting torch, it is presumed that the 
flame obtains what added oxygen is necessary from the cut- 
ting jet and this together with the velocity of the flame and 
its hydrogen enveloping flame permits the neutral flame 
to continue burning. 


(155) THOSE who are familiar with gasoline engines will 
know that after being used for some time, the impurities in 

FIG. 86. Removing Carbon from U. S. Army Truck, by the Oxygen Process, 
at the Ordnance Welding School. 

the lubrication oil and in the gasoline, which is continually 
being burned, will form around the top of the piston and 
cylinder head in the motor. When enough has been deposited 



and a few high points become overheated through long run- 
ning, there will be a metallic knock distinctly heard when an 
extra strain is being exerted by the motor. This layer 
of impurities is called carbon and its presence means loss of 
power. Owing to the construction of most cylinder blocks, 
it is a very difficult matter to reach this portion of the block 
without dismantling. This requires skilled labor and means 
much delay. A method of removing this carbon by the oxy- 
gen process has been devised, which will save much time and 

(156) To remove carbon from a gasoline engine, first 
shut off the gasoline in the line and allow the engine to run 
until all gas has been removed from the carburetor. This 
is merely a safety measure. If a vacuum feed is used, the 
vacuum tank is drained, as it would require much time for the 
engine to consume this amount of gas. The hood of the car 
is then removed and all parts of the motor on the side where 
the burning is to be done are covered with asbestos paper 
or by a heavy piece of canvas which has previously been 
dampened. This is to keep the sparks from dropping into 
the apron or oily parts of the machine. Remove the spark 
plugs and see from the condition of these spark plugs whether 
the cylinder is dry or oily. An oily cylinder will burn out 
much more rapidly than when dry. This can be detected 
very easily from the condition of the spark plugs. It is 
recommended that only the spark plugs be removed as the 
removal of the bonnet or any larger portion will require 
much more oxygen and will not produce as satisfactory 
results as when the oxygen is introduced through a small 

(157) Place the carbon removing apparatus, which con- 
sists of the oxygen drum, regulator, a length of hose and 
carbon burning torch, the latter being made up principally 
of a shut-off valve and a long length of small copper tubing 



as shown at A in Fig. 87 . Turn on not over twenty-five pounds 

oxygen pressure as far as the torch, and the apparatus is then 

ready to use. With the torch inserted through the spark 

plug hole in number one cylinder, that is, the one nearest 

the radiator, guide the rise of the piston until it is at the top 

of the stroke. This means that both intake and exhaust 

valves are closed. On automobiles where a self starter is 

used, it will be necessary to use a crank 

for turning over the motor. With the 

piston at the top of the stroke and both 

valves closed, there is only a small 

portion of the cylinder head to be 

worked upon and this is the part which 

has the carbon deposit upon it. All 

machined surfaces and valve seats are 

fully protected and will not be subjected 

to any exposure during the burning. If 

the cylinder seems very dry, a teaspoon 

of alcohol or kerosene may be sprayed 

into it through the spark plug port, to 

facilitate the clearing of the carbon. If 

the cylinder is somewhat oily, this is 

not necessary. A match or burning 

taper is then held over the hole and a 

stream of oxygen will carry the flame 

down into the cylinder and ignite the 

carbon. As soon as this occurs, a 

small cracking noise can be heard and the carbon will run 

around the inside of the cylinder in a heated condition. The 

part around the valves should be cleaned of! first, before 

going to the inner chamber, as this process does not seem to 

work very well if performed the other way. A roaring noise 

will be in evidence and the popping of the carbon from 

the surface as it frees itself may frighten the operator 

FIG. 87. Carbon Burn- 
ing Apparatus. The 
Small Copper Tube A 
is Flexible and can be 
Bent in any Shape 


when attempting his first job, but there is absolutely no 

(158) It must be remembered that oxygen itself does not 
burn, but merely assists the other inflammable material in 
burning, therefore it is only the carbon which is contained 
in the cylinder that in this case does the burning. As soon 
as this is all consumed, there will be nothing else to burn and 
the sparks will die of their own accord. When this occurs, 
the operator will shut off his torch, blow the cylinder out 
with compressed air and replace the spark plug and then 
proceed with the next cylinder, which he will treat in the 
same manner. He must be sure, however, that the piston 
in cylinder number two, or whatever cylinder he is working 
on, is moved to the top of its stroke and that both valves in 
that particular cylinder are closed before he starts his burn- 
ing. After all cylinders have been treated like number one 
and the spark plugs are in position, the gasoline is turned on 
(if the vacuum tank has been drained, it is best to fill this), 
and the motor started, with the exhaust " cut off " open, 
in order that any loose particles of carbon may be blown out. 

(159) While this process is in very common use, and 
seems to be very simple, there are many who go through 
the steps without obtaining satisfactory results. It is con- 
sidered best, if possible, in attempting carbon burning for the 
first time, to try it on some motor which is about to be over- 
hauled, in order that the results may be studied so that the 
operator will not go blindly on, without showing some im- 
provement. Many times only the high points are burned 
out, which will free the motor temporarily of some of its 
knocks, but within a week or so they will become evident 
again. He who will become proficient in learning carbon 
burning should apply himself and study his results. 

(160) There are those who consider carbon burning in- 
jurious to the motor on account of the high temperature flame 


which they think is introduced. But it is ignorance as to 
the working principle of this process that makes them think 
this. When it is considered that a gasoline motor depends 
upon a rapid succession of internal explosions for its power, 
the folly of condemning a process of this nature, where abso- 
lutely no actual flame is used, will be seen. It is only the 
incandescent particles of carbon flying about that give any 
heat at all. After a cylinder has been burned or decarbonized, 
the hand can be placed upon it immediately, without any 
fear of being burned. Those motors equipped with aluminum 
pistons may be handled in the same way as those of cast 
iron, and when properly used this method of decarbonization 
is very satisfactory. 

(161) Many times it is asked how often carbon burning 
is to be recommended. This will all depend upon the type 
of motor, its condition, and to some extent, upon the lubri- 
cating oil and gasoline used, as well as the mileage of the car. 
If a machine is being run continually, it may be necessary 
to have the carbon removed about every two months, but 
conditions will ter i to lengthen or shorten this time as the 
case may be. When the knocks are in evidence, and the 
loss of power is noticed, it is time for the carbon to be re- 
moved, and whether this is one month or two it is an error 
to continue running the car which is filled with carbon. 
Invariably the carbon burner is asked by his customer whether 
carbon burning will regrind valves; this and many other 
questions can be intelligently answered and explained to the 
questioner's satisfaction if a careful study of the process is 


(162) In drawing this elementary course in oxy-acetylene 
welding to a close, the author wishes to again call attention 
to the fact that this course is merely to be considered as a 



(Courtesy of the British Oxygen Co.) 

FIG. 88. Photograph Showing Square Piece Cut Out of a Steel Block 9 Inches 


(Courtesy of the Dains-P.ournonmlle Co.) 

FIG. 89. This is an Electrically Driven Oxy-acetylene Cutting Machine 
for Making Duplicate Cuts on Steel from a Drawing. Dies and many 
Irregular Forms may be Produced at Low Cost by it. 



foundation upon which to build. An effort has been made to 
confine the student's line of thought exclusively to the actual 
welding of the various metals and an intimate knowledge of 
the tools necessary to accomplish this. Technical terms have 
been avoided as much as possible, and history, as well as the 

(Courtesy of the Dams-Bournonville Co.) 

FIG. 90. This Shows a Motor-driven Oxy-acetylene Device Particularly 
Adapted to Cutting Plates or Sheets into Round, Oval, or Irregular Forms 
with either Straight or Beveled Edges. 

generation of the various gases, have been considered only of 
secondary importance and have been purposely omitted. 
Many repetitions have been made to place emphasis upon 
certain points and methods. It is hoped that the student 
who pursues this course if he has been restricted to the use 



of only one apparatus will realize that there are many 
such on the market, each one of which may have its advan- 
tages, but if the general rules, as outlined, are followed, he 
will not have much difficulty or be covered with confusion 
if called upon to operate different makes of apparatus for 

FIG. 91. Quick, Permanent Repairs are Made on Large Supply Trucks in 
the U. S. Army by its Corps of Trained Welders. This View Shows an 
Individual Welding Unit in Operation at the U. S. Army (Ordnance) 
Welding School. 

the first time. If he sees that there is gas pressure on his 
lines, he should not hesitate, thereby showing his ignorance 
of that particular type of apparatus, rather let him turn on 
one valve, and direct the stream of gas toward his nostrils. 
He can then readily determine whether it is the fuel gas or 
not and knowing that oxygen will not burn he can turn his 



(Courtesy of Ben K. Smith, V. S. Welding Co.) 

FIG. 92. This Cylinder did not Require to be Bored or have any other 
Machine Work Performed, but was Placed in Service Directly after 
Welding and has been Serving for over Three Years. 


fuel gas on and proceed without showing any concern. It 
might be said that confidence in one's self is the keynote of 
success, and this is imperative to make an expert welder, 
but to the man who studies the flame action on his metals 
and appreciates the apparatus to the fullest extent, there is a 
very bright future. 

(163) The welder who desires the best results should 
procure the best apparatus possible to fill his requirements. 
The cost of such is only of secondary importance, the hazard 
attached to cheaply constructed apparatus and the loss of 
gas, time and the execution of faulty work and the depre- 
ciation of the welder's reputation, are matters of vital im- 
portance. The supplies too, such as filler-rods and the like, 
should be obtained only from reliable welding companies 
who have their own shops in which they may test them. It 
is false economy indeed, to attempt to save a few cents on 
filling materials, for many dollars' worth of time and gas 
may be lost on account of the failure of the metal added. 

(164) There are a few illustrations set forth herein, to 
show what has been accomplished in the way of machine 
construction used in adapting the oxy-acetylene process to 
the requirements of various manufacturers. These will tend 
to show to some extent what the future has in store for this 
wonderful process. 

(165) It has been rightly stated that oxy-acetylene 
welding is yet in its infancy. The torches, regulators and in 
fact all parts of the apparatus are constantly being improved. 
The process of cutting cast iron must still be solved, so it 
will again be stated that it behooves those who are interested 
in this work to apply themselves to the great future in store 
for them. 



ACETONE. A liquid which is capable of absorbing twenty-five times 
its volume of acetylene gas under normal temperature and pressure. 
Employed as a solvent in the acetylene cylinder. 

ACETYLENE. An inflammable gas used for welding and cutting. 

ACETYLENE CYLINDER. A steel tank filled with porous material 
and acetone, in which acetylene gas is stored. 

ADAPTER. A brass fitting used to connect regulators to different 

ALIGNMENT. State of being in line. 

ALLOY. Metal which is added to another metal. A mixture of two 
or more entirely different metals. 

ANGLE IRON. A steel bar, the cross-section of which forms an angle 
of 90 degrees. 

ASBESTOS. A fibrous material not affected by fire. Usually supplied 
in sheets or shredded. 

AUTOGENOUS WELDING. The process of uniting two pieces of metal 
together by fusing without additional metal being added, and without 
the aid of hammering. 

BABBITTED. Lined with Babbitt metal. Generally found in bear- 

BACK FIRE. The popping out of the torch flame, due to a slight 
explosion of the mixed gas between the torch tip and the mixing chamber. 

BEARING. Support or wearing surface for a revolving shaft. 

BEVEL. To cut or form at an angle. 

BEVELED EDGE. An edge cut or formed at an angle. 

BLOWHOLE. A hole or cavity formed by trapped gas in metal. 

BLOWPIPE. A torch which mixes and burns gases producing high- 
temperature flames. The term TORCH is given preference in oxy-acety- 
lene welding and cutting. 



BRAZING. Uniting metals with brass or bronze by means of heat. 

BRAZING WIRE. A filler-rod of brass or bronze used in brazing. 

BUTT JOINT. A joint made by butting two edges together. 

CAP. A metal cover used to protect cylinder valves. 

CARBON BLOCKS. Carbon in block form. Used to assist in building 
up parts that are to be added. They may be ground to any shape 

CARBON RODS. Carbon in rod form. Employed to save holes 
around which the metal is melted. 

CARBONIZING FLAME. A flame with an excess of acetylene gas. 

CONTRACTION. The shrinkage of metal due to cooling. 

CROSS-BAR. Hand screw for adjusting the passage of gas through 
the regulator. 

CUTTING JET. Central jet of oxygen issuing from tip of cutting 

CUTTING TORCH. A torch with one or more heating jets and an 
oxygen jet, used for cutting metals in the oxy-acetylene process. 

CYLINDER. A tank containing gas under pressure. 

DUCTILE. That property which permits metal being formed or 
drawn into different shapes without breaking. 

EXPANSION. Increase in size due to heating. 

FILLER-ROD. A rod or wire used to supply additional metal to the 

FILLET WELD. A weld made in a corner. 

FLAME PROPAGATION. The rate at which a flame will travel. 

FLASH BACK. The burning back of the gases to the mixing chamber 
or possibly farther. 

FLUX. Chemical powder used to dissolve the oxides and clean 
the metal when welding. 

GAS. Erroneously applied to acetylene gas alone. Both oxygen 
and acetylene are in the form of gas. 

GAUGE. An instrument for measuring pressures of gases. 

GENERATOR. A device for manufacturing gas. Usually specified 
as acetylene generator or oxygen generator. 

GRAIN. The arrangement of the molecules or crystals which make 
up a metal. 

HORIZONTAL WELDING. Welding in a level position. 

I-BEAM. A steel bar with the cross-section of an I. Sometimes 
called EYE BEAM. 

LINE. Hose or pipe carrying gas. 


MANIFOLD. A header with outlets or branches by which several 
cylinders of gas may be used in batteries. 

MONEL METAL. An alloy of copper and nickel. 

NIPPLE. A short piece of pipe. 

OVERHEAD WELDING. Welding with the torch overhead. 

OXIDATION. A combination with oxygen. 

OXIDE. A coating or scale formed by oxygen combining with metal. 

OXIDIZING FLAME. A flame with an excess of oxygen gas. 

OXYGEN. A non-inflammable gas used in oxy-acetylene welding 
and cutting. 

OXYGEN CYLINDER. A steel tank for storing and shipping oxygen. 
Available for commercial work in 100, 200, and 250 cubic-foot sizes. 
The oxygen is compressed as free gas to 1800 pounds .pressure at 68 
degrees Fahrenheit. 

PEENING. Stretching the surface of cold metal by use of the hammer. 

PENETRATION. A thorough welding completely through the joint 
of the pieces or parts being fused. 

PREHEATING. The heating of a metal part previous to welding. 
Generally used to prevent strains or distortion from contraction and 
expansion; also to save gas. 

POOL. A small body of molten metal formed by the torch flame. 

PUDDLE STICK. A steel rod flattened at one end, used to break up 
oxides, remove dirt and build up additional metal. Particularly help- 
ful in welding cast aluminum. 

PUDDLING. The manipulation of the filler-rod or the puddle-stick 
in such a manner as to break up oxides, remove dirt, and aid in securing 
a good fusion of the metal. 

REDUCING FLAME. (See Carbonizing Flame.) 

REDUCING VALVE. (See Regulator.) 

REGULATOR. A device for reducing and maintaining a uniform 
pressure of gas from cylinders, generators or shop lines. 

SCALE. A coating of oxide on fused iron or steel that breaks off as 
the metal cools. 

SCALING POWDER. A name given flux. 

SLAG. The oxidized metal and scale blown out when cutting. 

SOLDERING. Uniting metals by fusing with a different metal which 
has a much lower melting-point than the pieces to be joined. The use 
of a lead, tin and zinc alloy is called soft soldering. Hard soldering is 
similar to brazing. 

TACKING. Fusing pieces together at one or more places. 


TIP. A copper or brass nozzle for a welding or cutting torch. 

V. Angle or groove between two beveled edges prepared for welding. 

V-BLOCK. Block cut out in the shape of a V, or angle iron, used in 
lining up shafts. 

VALVE. A device for shutting off the passage of gas. 

VERTICAL WELDING. Welding as applied to an upright position. 

WELDING ROD. Material used to supply additional metal to the 
weld. (See Filler-rod.) 


NOTE. In order to determine whether the student is obtaining 
the information desired it is sometimes thought fitting to give written 
examinations. These serve as an index as to what the student has 
learned and what he has not. They also let the instructor know 
whether he is making every point clear in his training. 

The following questions fit in with each chapter or part thereof 
and are merely a suggestion for the instructor who has no course of 
training outlined. With one or two exceptions all answers to these 
questions may be found within the manual. There are a few mislead- 
ing questions purposely inserted to see if the student is thinking for 



1. Name the different classes into which oxy -acetylene welding 
paratus may be divided and explain the principles upon which this 

classification depends. 

2. Illustrate by line sketches the various locations of the mixing 
chambers for the oxygen and acetylene gases in welding torches. 

3. (a) Where is the logical location for the mixing chamber in 
welding torches employed in automobile and tractor repair work? 

(6) Give reasons for so thinking. 

4. How is the torch and the welding tips treated after repeated 
"flash-backs" have taken place? 

5. Describe briefly the working principles of a regulator and illus- 
trate with a simple sketch. 

6. Explain the difference between high and low-pressure regulators. 

7. (a) Can acetylene regulators be interchanged with oxygen 
regulators with perfect safety? Explain why. 

(6) How is it possible, in majority of cases, to distinguish in a very 



simple manner, between oxygen and acetylene regulators, when no 
gauges are attached? 

(c) Why does this difference exist? 

8. (a) Why should all tension upon diaphragm springs be removed 
before admitting gas under pressure to the regulator? 

(b) Can a regulator which has been abused in this manner be 

(c) What can be employed as a fitting substitute for gallilith? 

9. Explain why the high-pressure gauge on the acetylene regulator 
cannot be used as an index to the contents of the attached cylinder of 
gas in exactly the same manner as the oxygen high-pressure gauge. 

10. Why is glycerine used as a substitute for oil when regrinding 
torch valve-seats with emery powder, and with lead-oxide in the 
caulking of leaky joints along the line? 


1. (a) Under what pressure is oxygen gas received in the cylinders 
used commercially? 

(b) Does this pressure vary to any great extent with changes in 

2. (a) Under what pressure is acetylene gas received in the cylinders 
used commercially? 

(b} Does this pressure vary to any great extent with changes in 

3 (a) In setting-up apparatus for the first time, or in attaching 
regulators to new cylinders, what precaution should be observed 
regarding cross-bar on regulators before the gas is turned on? 

(6) Where should the operator stand when turning on the gas? 

4. (a) How much pressure should be placed on the oxygen hose, 
when the torch-valves are closed, before starting to operate with a 
medium-sized tip? 

(b) How much pressure should be placed on the acetylene hose, 
when the torch-valves are closed, before starting to operate with a 
medium-sized tip? 

5. (a) After both the oxygen and acetylene gases are in the line 
hoses as far as the torch, which valve on the torch is opened first in order 
to light? 

(b} What would happen if the other torch-valve were opened first? 


(c) What would likely occur if both valves were opened before torch 
was lighted? 

6. (a) How is it possible, when lighting torch, to determine whethe 
enough pressure is on the acetylene line without looking at gauge? 

(b) How is it possible, in the case of oxygen pressure? 

7. (a) What is meant by a neutral flame? 

(b) How hot is a neutral oxy-acetylene flame? 

(c) Is the temperature of a neutral flame the same whether large or 
small tip is used? 

8. (a) If too much acetylene gas is used, how will the flame be 

(b) What action will this have on the weld? 

9. (a) If too much oxygen gas is used, how will the flame be affected? 
(b) What action will this have on the weld? 

10. (a) Explain briefly how apparatus is shut-off, when not to be 
used for several hours or more. 

(b) Why should particular care be taken to see that acetylene cyl- 
inders are tightly closed when empty? 

(c) What action does oxygen have on oils and greases? 



(Part One) 

1. (a) How is it possible to distinguish cast iron from such metals 
as malleable iron? 

(b) From semi-cast iron? 

(c) From cast steel? 

2. (a) What kind metal is used in making "filler-rod" used in the 
welding of cast iron? 

(b) What general rule can be laid down as to the relation of the metal 
in the "filler-rod" to the metal to be welded? 

3. (a) What are the characteristics of good cast iron "filler-rods"? 
(b) Can piston rings and other small scraps of cast iron be used 

successfully as "filler-rods"? Explain why. 

4. (a) What is the purpose of a flux? 

(b) Is a flux used in the welding of cast iron? 

5. (a) Name one formula for making a cast-iron flux? 

(b) How often is the flux applied, and by what means? 

(c) In what condition are fluxes kept when not in use? 


6. (a) How should the flame be held in the welding of all cast iron? 
(b) When and how is the "filler-rod" added to the weld? 

7. (a) Name the one principal cause of blow-holes and hard spots 
in the weld. 

(b) Mention some of the others. 

8. (a) When is it advisable to grind, or " V " out, the ends of the pieces 
to be welded? 

(b) When is it not advisable? 

9. (a) Does the application of heat cause contraction or expansion in 

(6) Are there any excepts to this rule? Name one. 

10. (a) Were two cast-iron bars measuring 2X12 inches and ^-inch 
thick, to be welded, end to end, what precaution should be observed in 
laying out, if the finished job is to measure just 24 inches long? 

(b} In what respect would this problem differ were the bars only 6 
inches originally and the finished job to measure 12 inches overall? 

(c) Is the action of the metal in the weld a constant, or a variable 
quantity depending upon the length of the bar in this problem? 


(Part Two} 

11. (a) How could a spoke, broken midway between the hub and rim, 
of a 24-inch, 4-spoke wheel (otherwise intact) be welded without pre- 
heating? (Use a sketch if necessary to make method clear.) 

(b) If a wheel of like size were broken only in the rim, midway 
between spokes, explain procedure in welding without preheating. 

(c) Same sized wheel, broken only in hub; can weld be made without 
preheating? Give reasons for so thinking. 

(d) Were breaks (a), (b) and (c} all present in same wheel, with rim 
fracture on opposite side of adjoining spoke from break in hub, should 
welding be started at rim or hub? Why? 

12. (a) In the building up of broken or missing teeth in cast-iron 
gears, what procedure is necessary when no carbon blocks are available 
for forms? 

(b) If certain carbon centers from dry cell batteries are obtainable 
how should they be treated before allowing molten metal to come in 
direct contact with them? 


(c) What very important point must be uppermost in mind when 
dental work on gears is being done? 

(d) Explain precautions taken in allowing work of this nature to cool. 
13. .(a) Realizing that hard spots occur in most welds executed by 

the new welder and having learned the cause of their presence and 
how to overcome them, would it not be possible to utilize this process 
for hardening parts which were subject to much wear and little 
strain? Explain procedure. 

(b) Why is it necessary to preheat such pieces as the following before 
the weld is attempted; broken water-jackets on gas-engine cylinders, 
usually brought about by freezing, and holes or cracks in crank 
cases, caused by the loosening of a connection rod; when lugs on the same 
cylinder, the arms on the same crank case can be welded without pre- 
heating, and ofttimes without even dismantling the motor? 



(Part Three) 

14. Describe fully the manner in which two cast-iron bars measuring 
i X6 inches and 24 inches long, are welded end to end, citing preparations, 
precautions, and the procedure and materials necessary to execute and 
carry the weld through to a cool state. 

NOTE. Both gases are in the line hoses as far as the welding torch. 

(Part Four) 

15. (a) Are water jackets on cast-iron cylinder blocks welded in a 
cold, or a preheated condition? 

(b) Is this true under all conditions? 

(c) If a crack were found in the combustion head of a cylinder block 
and the entire water jacket and cylinder were cast in one, how should this 
job be prepared in order to make a successful weld? 

(d) In welding a broken lug on the base of a cylinder block how should 
lug appear after weld is cold? 




1. Describe the operation, step by step, taken to set up an oxy- 
acetylene welding plant, from the assembling of the parts, right through, 
until a neutral welding flame is obtained. (If a sketch, with the gas 
cylinders and parts numbered i, 2, 3, etc., will assist in making descrip- 
tion clear, it may be used.) 

2. (a) Is it desirable to have a planed metal, or a brick-top table for 
welding purposes? 

(6) Explain why. 

3. Outline and describe briefly, a simple method of building a popular 
type of welding table. 

4. (a) What is the name and style of bricks used in the welding shop? 
(b) Name at least three purposes for which these bricks are used. 

5. (a) Why does an emery wheel play such an important part in the 
oxy-acetylene welding industry? 

(b) Why is it desirable to have a flexible shaft attachment for the 
emery wheel, if possible? 

(c) Name some of the important things a flexible shaft attachment 
is used for in the preparation and finishing of welds. 

6. (a) In what kind of containers is retort cement purchased in the 
commercial world? 

(b) Where is retort cement used in the welding shop? 

(c) How does it differ from the ordinary clay or putty? 

7. (a) Why should a blacksmith forge be added to the welding 
shop equipment if one is obtainable? 

(b) What two important tasks is a forge used for in the welding 

8. (a) It is essential that several pails of water be located throughout 
the shop; why should this be necessary? 

(b) Mention a few instances where water is required in the welding 

9. Explain fully why great care should be exercised in ventilating a 
shop where commercial welding is being done. 

10. (a) Describe one simple method of constructing a flux box. 
(b) What advantages has this type of container? 


Subject REPAIRS 

1. What is the best method of locating a leak in either the oxygen or 
acetylene lines? 

2. If a leak were found in a ground seat, how could it be stopped if 
the nut on the coupling had been screwed up as far as possible? 

3. Name one method of attaching connections to hoses so that tkey 
will not blow off or pull off when pressure is applied. 

4. How could either an oxygen or acetylene hose that had been 
burned or otherwise injured, be repaired to withstand the gas pressure? 

5. How could regulator be operated if the cross-bar for applying pres- 
sure upon the diaphragm springs were lost? 

6. (a) What procedure would be necessary to make connection if 
cylinder were supplied with an adaptor which would not fit the regulator 
connection and it could not be coupled up directly? 

(b) Realizing that all cylinder connections about a regulator are gen- 
erally supplied with a ^-inch taper pipe thread, why do all manufacturers 
solder them in? 

7. Explain why oxygen high-pressure gauges are constructed with a 
loose back and a solid front. 

8. (a) Where is the first place to seek trouble in a gauge if it leaks? 

(b) Can such leaks be repaired? 

(c) Describe method. 

9. If either a high- or low-pressure gauge were injured beyond the 
repair state how could welding plant be kept in operation without it? 

10. (a) What would be the trouble, in shutting off a welding plant, 
if there were a reading on the high-pressure gauge and none on the low- 
pressure gauge, after permitting gas to escape from the hose? 

(b) How could the reading on this gauge be brought back to zero? 


(Part One) 

1. (a) Is the welding of steel more or less difficult than cast iron? 
(b) Explain why. 

2. (a) Why is the choice of the welding tip so important when working 
on steel? 


(b) What will result if the tip is too large? 

(c) If too small? 

3. (a) Why is the choice of a "filler-rod" of a correct size so impor- 
tant for steel welding? 

(b) What will happen if the "filler-rod" is too large? 

(c) If too small? 

4. (a) What kind of a "filler-rod" is used in welding steel? 

(b) Give a general rule covering relation of "filler-rod" to the metal 
being welded in all cases, but one or two. 

(c) Name one exception. 

5. (a) Is a flux (or scaling powder) necessary in welding steel? 
(b) Explain why. 

6. (a) How is the flame adjusted for steel welding? 

(b) What kind of a flame is generally used in finishing steel work? 

(c) Why is this done? 

7. (a) How is the flame held when executing a steel weld? 
(6) How is the "filler-rod" held when making a steel weld? 

8. (a) Is it necessary to "V" out on steel the same as on cast iron? 
(b) Explain why. 

9. (a) Is a steel weld as strong as the original metal if not built up? 
(b) Explain why. 

10. (a) Is the same provision made for expansion and contraction 
on steel as on cast iron? 

(b) Give reasons for so thmking. 


(Part Two} 

11. (a) What is meant by a "crater" in steel welding? 
(6) How are they removed from the weld? 

12. (a) What are some methods and marks of distinguishing steel 
from other metals? 

(b) How is cast steel distinguished from cast iron? 

13. (a) Name some of the qualifications of a good "filler-rod" for 
mild steel welding. 

(b) In what manner does the "filler-rod" differ for the alloyed and 
high-carbon steels? 

14. (a) In bringing the neutral flame in contact with the metal on a 


steel weld, should the cone bend and spread on the surface, or just 
lick it? 

(b) Explain why. 

15. (a) What is the principal cause for hard spots in steel welds? 
(b) What causes some of the others? 

16. (a) Is it rolled steel or cast steel that does not expand when 

(b) Name one other metal that does not expand when heated. 

17. (a) Why are welds more difficult on sheet iron and steel than on 
some of the heavier pieces? 

(b) What can be used as a "filler-rod" on sheet metal work? 

18. (a) What difficulty is generally encountered, when making a 
long weld like on a steel tank? 

(b) How can this be overcome? 

(c) Why do the open ends on sheet steel welds overlap in welding 
when same class of work on cast iron separates? 

19. (a) What causes steel welds to carbonize? 
(6) What usually causes a burnt steel weld? 

20. Describe fully how a broken automobile frame can be welded 
and re-enforced to make it stronger than originally. 


(Part Three) 

21. (a) What kind of a "filler-rod" is used in welamg cast steel? 
(b) Is a flux used? 

22. (a) What kind of a "filler-rod" is employed when welding cast 
iron to steel? 

(b) What kind of a flux is used? 

23. (a) Can springs be successfully welded? 
(b) State reasons. 

24. (a) Why are crank-shaft welds so hard to execute successfully? 

(b) What kind of a "filler-rod" is used for best results on most 

(c) What points does the welder consider when deciding whether a 
weld of this nature is advisable? 

25. (a) Briefly describe the method of building up crank-shaft bear- 
ings that have been worn down. 


(b) What are some of the precautions taken in work of this kind? 

26. (a) When automobile propeller shafts and rear axles break, it is 
generally adjoining the square end. Is it advisiable to weld this short 
piece on? 

(b) What is the correct procedure in a case of this kind? 

27. (a) If a case-hardened ring-gear is to have its teeth built up or 
new ones added, how is it handled after welding? 

(b) Should all case-hardened work be so treated after welding? 

28. (a) In welding two pieces of metal, one of which is considerably 
lighter than the other, how is the flame held in order to bring both pieces 
to a fusion at the same time? 

29. (a) If a steel weld were to break in the line of weld, how should it 
be prepared if it is to be rewelded? 

(b) Does this procedure apply only to steel? 

30. Were a hole 6 inches square in a sheet of steel to be welded up 
without preheating, what would be the approximate size of the patch 
necessary and how would it be prepared, in order to take care of the expan- 
sion and contraction strains? 

(Part Four) 

li. (a) Why should a steel weld of any kind be executed as rapidly 
as possible? 

(b} What will happen if steel is kept in a heated condition too long? 
(c) Why should a change be in evidence under these conditions? 

32. (a) Explain what is meant by a "dished" patch, for boiler or 
thin armor plate? 

(b) Draw such a patch. 

(c) How is a patch of this nature prepared? 

33. (a) What is meant by a "corrugated" patch for boiler or thin 
armor plate? 

(b} Sketch such a patch. 

(c) How is this kind of a patch prepared? 

34. (a) What advantages has a "corrugated" patch over one that is 

(b) Where are "corrugated" patches used extensively? 

35. (a) How are boiler flues prepared for re-tipping? 


(b) Sketch a simple jig for holding such pieces in place for welding. 

36. (a) Describe how lengths of various sized pipe can be welded 
together end to end. 

(b) What precautions are necessary when executing such welds? 

37. (a) When welding large steel castings why is it almost always 
advisable to preheat the work? 

(&) Why is preheating so necessary on vanadium and other alloyed 

38. Why is it desirable to chip out the sand and thin scale formations, 
in and around blow-holes in steel castings before filling in? 

39. (a) Why do the majority of good welders bend their steel "filler- 
rods" at right angles about 6 inches from the end? 

(b) Why isn't this being done on cast iron? 

40. (a) What advantage is there in making a vertical weld from the 
top down, rather than starting from the bottom and working up? 

(b) In welding overhead why is it so important that the work be in a 
molten state before adding the "filler-rod"? 

(c) In overhead welding, why doesn't the metal drop when in a molten 



1. Explain fully which parts of an oxy-acetylene cutting plant are 
different from a welding unit. 

2. (a) If there is a difference in either of the regulators, mention 
which one it is. 

(b} What is the difference? 
(c) Why is it necessary? 

3. (a) Is it possible to weld with a cutting torch? 

(b) What precaution is necessary if this is done? 

(c) Why isn't this process used? 

4> Explain how cutting can be done with the welding torch if neces- 

5. (a) In cutting by the oxy-acetylene process, which does the 
cutting, the oxygen jet or the neutral flame? 

(6) What action has the oxygen jet on the metal? 
(c} What part does the neutral flame play in cutting? 

6. Can oxygen or acetylene under sufficient pressure be made to cut . 
individually? Explain fully. 


7. Why is it specially important that armored hose be used on the 
oxygen line when making heavy cuts? 

(Give at least two reasons.) 

8. (a) How is a cutting torch lighted? Describe in detail. 
(b} How is cut started on metal? 

(c) How is torch held in regard to metal being cut? 

9. (a) Is it possible to successfully cut cast iron? 

(b) Wrought iron? 

(c) Cast steel? 

(d) Rolled steel? 

10. (a) Cutting can be done under water with ordinary cutting appa- 
ratus; why doesn't the flame go out when submerged? 

(b) What additional equipment is generally used in underwater 


1. Explain as fully as possible the chief characteristics of a good 
"filler-rod" for brass welding. 

2. (a) Is a flux used in welding brass? 

(b) What is one way of making a good flux for brass? 

3. (a) What kind of a flame is used in brass welding? 
(b) Why? 

4. (a) In what position is the flame held in welding brass? 
(b} How should the "filler-rod" be held? 

5. (a) Is it advisable to " V" out or burn off the ends of brass work to 
be welded? 

(b) Explain why. 

6. (a) What causes the dense white fumes to appear when fusing 

(b) What is cause of brass welds being porous? 

7. Why should brass work not be disturbed when red hot? 

8. What is the most difficult part of brass welding as a whole? 

9. Why are brass welds generally cooled in water as soon as fusion is 

10. Why is it difficult for the beginner to weld heavy pieces of 



1. (a) Can malleable iron be successfully welded? 

(b) What is the most successful method of joining two pieces of malle- 
able iron? 

2. What are three methods of detecting malleable iron? 

3. (a) What kind of "filler-rod" is used on malleable iron? 

(b) Are " filler-rods " of malleable iron satisfactory? 

(c) What kind of flux is used on malleable iron work? 

4. (a) How is a malleable iron casting prepared for welding? 

(b) How hot should work be, previous to adding "filler-rod"? 

(c) What will occur if too much heat is applied? 

5. (a) In what respect does the adjustment of the flame differ on 
malleable iron from that of cast iron and steel? 

(b) How is the flame held in relation to the work? 

(c) Does the flame come in direct contact with the "filler-rod"? 

6. (a) Is more, or less, surface covered by the "filler-rod" on malle- 
able iron than on cast iron? 

(b) Why? 

7. (a) How should malleable iron be cooled? 
(b) Is this the same as in welding brass? 

8. On what part of machinery does a welder generally expect to find 
malleable iron castings? 

9. Explain carefully how a malleable iron automobile, axle or trans- 
mission, housing that has been cracked or broken, can be re-enforced 
so that it will be stronger than ever. 

10. Describe very briefly how malleable iron is made and in what 
respect it differs from cast iron when cold, and also when under the influ- 
ence of the oxy-acetylene flame. 


1. (a) Explain what is meant by carbon burning. 
(b) In what respect is it used extensively? 

2. (a) Will oxygen gas burn alone or does it merely aid combustion? 
(b) Will carbon in a free state burn? 

3. (a) Why is it advisable to remove only the spark plugs and not 


the entire valve cap or "bonnet" when burning carbon in a gas 

(b) Can it be done either way? 

4. (a) Does it make a difference if the carbon is hard and dry in the 

(b) What will help in such cases? 

5. (a) If the cylinder is rather oily does this make a difference? 
(b) Does the presence of oil aid or retard combustion? 

6. (a) What precautions are necessary before carbon burning is 

(b) How is asbestos paper used in carbon burning? 

(c) Name a good substitute for asbestos paper when carbon burning. 

7. (a) Is there any danger of warping the valves and overheating the 
cylinder and piston when burning carbon? 

(b) What is the effect of carbon burning on aluminum pistons? 

8. (a) What pressure is used on the oxygen line for carbon burning? 
(b) Will carbon burning re-grind valves? 

9. (a) How long should the burning be done? 

(b) How often is carbon burning recommended for a gas engine? 

(c) If there are any carbon particles or sand left in the cylinder after 
burning is done how are they removed? 

10. Describe how the carbon is removed from a four-cylinder engine, 
paying particular attention to details such as lighting, which part of the 
head the torch is played on first, what does the burning and where the 
carbon goes. 


1. (a) What is meant by preheating as applied to the oxy-acetylene 
welding industry? 

(b} What are several fuels which can be used very successfully for 

2. Name the three principal reasons why parts to be welded are gen- 
erally preheated. 

3. (a) Why is charcoal considered the best preheating agent for gen- 
eral welding? 

(b} Why should it not be used to any great extent in closed rooms dur- 
ing the winter months? 


(c) If used during the winter what precautions are observed? 

4. (a) Mention two materials which are used extensively for building 
up ovens and doing the preheating. 

(b) What kind of brick is used? 

5. (a) How much should cast iron be preheated? 

(b) Brass or bronze? 

(c) Aluminum? 

6. Sketch and describe how a temporary brick preheating oven should 
be built, giving all dimensions, such as: length, width and height and 
reasons for them. 

7. Explain how a cylinder block with a broken water jacket is set 
up for preheating; how oven is built for charcoal fire; how fire is started ; 
how block is protected while welding and how it is returned to a cold 

8. (a) What precautions are necessary in setting up and preheating 

(b) If piece is to be turned while in the fire, what provision is made in 
building up oven? 

9. In which cases is preheating absolutely necessary in order to make 
a satisfactory weld? 

10. (a) Give a sketch showing a preheating torch for use on illuminat- 
ing gas and compressed air, which can be constructed very easily. 

(b) Why are preheating torches not popular for general welding? 

(c) Where are they used in numbers? 

(Part One) 

1. (a) Is the welding of aluminum, more or less difficult than such 
metals as cast iron and steel? 

(b) Explain why. 

2. (a) Name the two methods of making aluminum welds. 

(b) Can they be combined? 

(c) Why? 

3. (a) What kind of a "filler-rod" is used in welding aluminum? 
(b) Is a flux used? Why? 

4. (a) Is a cast or drawn " filler-rod " preferred? 

(b) Name the two important metals which should be present and the 
percentage of each in the "filler-rod." 


5. (a) How should the flame be adjusted for aluminum welding? 
(b) How is the flame held in relation to the work? 

6. (a) How is the "filler-rod" added? 

(b) In what respect does this differ from all other metals? 

(c) Why can this be done? 

7. (a) Name the principal characteristics of aluminum with regard 
to heat. 

(b} What other metal acts in a similar manner? 

8. (a) Is it necessary to "V" out aluminum for the same reasons as 
other metals? 

(6) Explain why. 

9. (a) Will an aluminum welding be as strong as the original? 
(b} Give reasons. 

10. (a) What kind of a tool is used to aid in making an aluminum 
weld by most welders? 

(6) How is such a tool made? 


(Part Two) 

11. (a) What kind of files are used to finish aluminum welds? 
(b) In what respect do they differ from the ordinary kind? 

12. (a) In which hand is the welding torch held in aluminum work? 

(b) In which, the "filler-rod'"? 

(c) The puddle stick? 

13. (a) What materials are used to "back-up" aluminum work for 

(b) Describe fully how aluminum is "backed-up" previous to pre- 
heating, in order to prevent the collapse of metal while welding. 

14. (a) How quick does the heavy coating or aluminum oxide form 
on a clean hot piece of aluminum? 

(b) Will the metal flow together when this oxide is present? 

(c) How is it overcome? 

15. (a) Is it advisable to weld aluminum from one side only or from 
both sides? 

(b) Why? 

16. In preheating aluminum with charcoal, what precautions are 


taken in setting up; in starting the fire; during the welding operation, 
and in cooling the piece? 

17. (a) Are preheating torches played directly on aluminum work? 
(b) What kind of an oven is used? 

1 8. (a) Is it necessary to heat the whole of an aluminum crank-case 
if one part has to be preheated? 

(b) Give reasons. 

19. (a) Are clamps used to hold parts in place on preheated aluminum? 
(b) Explain why. t 

20. When starting to weld a cold piece of aluminum, the flame is 
brought in contact with the work and held there much longer than on a 
similar size piece of steel before any apparent change occurs. How is 
this accounted for, knowing that aluminum has a much lower melting 
point that steel? 



(Part Three) 

21. Explain fully why it is necessary to employ greater speed 
in the welding of aluminum than on any other metal? 

22. (a) What is retort cement? 

(b} How does it differ from ordinary clay? 

(c) For what purpose is it used in aluminum welding? 

23. (a) When performing an aluminum weld by the puddle system, 
is the welder dependent upon the flame, the "filler-rod" or the puddle 
stick, for the fusion of the metal? 

(b) Give explanations. 

24. (a) What method of welding is used when executing a vertical 
weld on aluminum? 

(b) Why isn't the other method used? 

(c) Is the vertical welding of aluminum to be avoided? 

25. (a) Can aluminum welds be made overhead? 
(b) Explain why. 

26. (a) Is the same method used on aluminum as in cast iron in 
welding from the closed end, toward the open? 

(b) Is this procedure necessary on preheated work? 

27. (a) If a suspension arm, of a "U" type, on an aluminum crank 


case were to break about 3 or 4 inches from the body of the case, could it 
be welded in place without dismantling the motor? 

(b) Explain in detail how such an arm should be welded. 

28. Due to the contraction and expansion, it is very difficult to 
have the bolt hole, in the end of an aluminum suspension arm that has 
been welded, return exactly to its former position. How is this diffi- 
culty provided for? 

29. (a) Should a section of an aluminum crank case be missing, would 
it be advisable to build up a new part with the "filler-rod" or to cast a 
new part in a mold and then weld it in? 

(b) Under what conditions should the above be done? 

30. (a) If it were found that an aluminum crank case after being 
welded, had one corner about f-inch lower than the rest of the case and 
it had not affected any of the bearings, could it still be reclaimed? 

(b) Give procedure. 


Absorbent, acetone as an, 26, 31 

asbestos as an, 31 

charcoal as an, 31 

mineral wool as, 81 
Acetone as an absorbent, 26, 31 
Acetylene cylinders, construction of, 

Acetylene gas, temperature of flame 

of, i 

Adapter, types of, 46 
Aluminum, backing up in welding, 114 

charcoal in welding, 116 

contraction and expansion in 

welding, 116 

clamps, use of in welding, 115 

crank cases, welding, 118 

filler-rods in welding, 112, 115 

flux method of welding, 109, in 

oxidation of bright surfaces in 

welding, 113 

preheating in welding, 1 16, 117 

preheating, method of, 52 

puddle and flux systems of 

welding compared, 1 1 1 

puddle method of welding, 109, in 

strains, avoiding internal, 118 

suspension arm of crank case, 

repairing, 118 

tip used in welding, 109 

welding, 109-117 

welding from one side, 1 14 
Apparatus, classes of welding, 19 

desirability of securing the best, 


Apparatus, emery wheel, need of, 41 

high-pressure welding, 20 

low-pressure welding, 19 

medium-pressure welding, 19 

metal top table, disadvantages 

of, 39 

mixing chambers, 21 

oils and grease to be avoided, 37 

oxy-acetylene, for cutting, 125 

regulator, 22 
- types of, 24 

required in welding, 19-26 

replacing lost cross-bar, 46 

setting up, manner of, 31, 32 

shop equipment, 39, 43 

shutting off, procedure in, 35 
Apparatus repairs, 44-50 

adapters, types of, 46 

gauges, operation of, 49 

gauges, safety, 47, 48 

hose clamps, 45 

hose, repairing leaky, 45 

leaks, method of locating, 44 

leaky threads, repairing, 44 
Asbestos as an absorbent, 31 

in aluminum welding, 116 

paper cover protection, 55 
Automobile frame, welding, 91 
Automobile, propeller shafts, welding, 

Axles, automobile, welding, 95 


Blow holes, causes of, 65 
Boiler flues retipping, 98, 99 




Boiler, "corrugated" patches, 102, 103 

"dished" patches in repairs to, 101 

"L" patches in repairing, 103 

repairing, 99-101 
Borax as a brass flux, 107 
Brass, alloy of, 106 

filler-rod in welding, 106 

flux in welding, 107 

fumes in welding, 108 

melting-point, 106 
Brass welding, 106-108 
Bronze for welding purposes, 123 

welding malleable iron with, 121 

Carbon burning, 135-144 

in gasoline engine, 136-139 

theory of, 139 
Carbonizing flame, 34 
Cast iron, welding of, 58-80 

blow holes, causes of, 65 

charcoal as preheating 

agent, 76 

combustion head of cyl- 

inder, repairing, 78, 79 

contraction of metals in, 

prevention of, 71 

expansion and contrac- 
tion of metals, 65-67 

filler rod, 61 

flux a cleansing agent, 61 

flux, manner of applica- 

tion of, 62 

flux, simple substitute 

for, 6 1 

gasoline engine cylinder 

block, repairing, 75, 76 

gear wheel teeth, three 

ways of restoring, 
broken, 71-74 

hardening parts by use of 

carbonizing flame, 74 

lugs, welding on cylinder 

block, 80 

Cast iron, welding of, methods of 
distinguishing metals, 

preparations for, 67 

procedure in, 63, 64, 67-70 

successful weld, criterion 

of, 75 

tip, size of, 63 

Cast steel, procedure in welding of, 88 
Charcoal as an absorbent, 31 

as preheating agent, 76 

in aluminum welding, 116 
Clamps, inadvisable in welding alum- 
inum, 115 

Contraction and expansion in alum- 
inum welding, 116 
in preheating, 53 

in welding steel, 87 

Contraction of metal in welding, pre- 
vention of, 71 

"Corrugated" patch, method of mak- 
ing, 102, 103 

Crank cases, aluminum, repairing, 118 
Crank shafts, welding methods, 93, 94 
Crater, development and removal of, 


Cross-bar, replacing lost, 46 
Cutting by oxy-acetylene process, 6 
Cutting with oxy-acetylene, 125-134 
Cutting torch, welding torch and, 

compared, 127 
Cylinder block, repairing cast-iron 

gasoline engine, 75, 76 
Cylinder bore, device for polishing, 

Cylinders, acetone as absorbent in, 26 

Decarbonization of automobile en- 
gines, 136, 139 
Demand for oxy-acetylene operators, 

"Dished" patch in boiler repairs, 101 




Emery wheel, value of in welding 

shop, 41 
Expansion and contraction of metals, 


in welding, 87 
Explosions, precautions against, 37 


Feather flame, 33, 35 
Filler rod, 89 

in brass welding, 106 

in welding malleable iron, 122 

metal in, 61 

used in aluminum welding, 112 

used in welding steel, 82, 91 
Fire brick, in aluminum welding, 116 

preheating oven of, 54 

table, 39 
Flame, carbonizing, 34 

feather, 33, 35 

neutral 33, 35 

oxidizing, 34 

torch, cutting under water with, 


varieties of, adjustment of, 32, 33 
Flashbacks, causes of, 21, 22 

prevention of, 22 

Flux, application, manner of, 62 

container, 42 

in brass welding, 107 

office of, 6 1 

substitute, a simple and effective, 


Gasoline engine, carbon, how to 

remove from, 136-139 
Gasoline tanks, necessity for caution 

in repairing, 103 
Gauges, operation of, 49 
safety, 47, 48 

Gear wheel teeth, three ways of 

restoring broken, 71-74 
Glossary, 145-148 
Goggles, eye, 35 

Hardening parts through use of car- 
bonizing flames, 74 
Heat in welding malleable iron, 123 
High-pressure regulated, 24 
Hose, armored, used on oxygen line, 


clamps in reparing, 45 
- leaky, 45 


" L " patches, 103 
Leaks, method of discovering, 44 

repairing threads, 44 
Lectures, 149-166 
Low-pressure regulator, 24 

Lugs, welding on cylinder block, 80 


"Maine," battleship, wreck cut up 

with oxy-acetylene gas, 6 
Malleable iron, bronze, welding with, 
121, 123 

clean surface, necessity of in 

welding, 122 

heat in welding, 123 

melting to be avoided, 121 

preheating unusual, 123 

steel strips in welding, 1 23 

welding, 1 20-1 24 

Metals, methods of distinguishing, 


Mineral wool as an absorbent, 31 
Mixing chamber, 21 


Needle valve, regrinding leaky, 26 
Neutral flame, 33, 35 



Oils and grease, importance of avoid- 
ing use of, 37 

Operation in oxy-acetylene welding, 

Operator, standing position of, re- 
lative to work, 32 

Overhead welding, 105 

Oxidation of bright surfaces in alumi- 
num, 113 

Oxidizing flame, 34 

Oxy-acetylene, cutting metals with, 

flame, varieties of adjustment of, 


in airplane construction, 9 

in automobile manufacture, 10 

in boiler shops, 10 

in brass and copper work, 10 

in commercial welding, 1 1 

in electric railways, 1 1 

in foundries, 1 1 

in lead burning, 12 

in lumber mills, 12 

in machine shops, 12 

in manufacturing, 12 

in mines, 13 

in pipe work, 13 

in plate welding, 13 

in power plants, 13 

in railroad work, 13 

in rolling mills, 14 

in sheet metal manufacture, 15 

in shipyards, 15 

in the forge shop, 1 1 

in tractor industry, 16 

lake boats cut apart by, 8 

operators, demand for, 17 

scrap cut up by, 6 

scrap yards, 15 

structural steel, 15 

torch as fire department tool, 7 

torch can be used under water, 8 

varied uses of, 9 

Oxy-acetylene cutting, 125-134 

apparatus for, 1 25 

arrangement of oxygen line, 125 

cutting torch, extemporizing a, 


flame, cutting under water with, 


flickering of oxygen jet, 127 

high-pressure and low-pressure 

regulators compared, 127 

hose, armored, in, 133 

pressure of acetylene and 

oxygen, 129 

steel and cast-iron, 131 

torch in preparing steel, 131 

torch, cutting and welding com- 

pared, 127 

torch, using cutting, for welding 

purposes, 133 

Oxy-acetylene welding, apparatus re- 
quired in, 19-26 

a fusing process, 62 

auto-frame repairs, 4 
classes of apparatus, 19 

containers, seamless, made 

through use of, 3 

definition of, i 

fire-brick table, 39 
future of, 1 7 

growth of process, 8 

locomotive frames, 4 

metal-top table, disadvantages 

of, 39 

mixing chambers, 21 
operation in, 27-38 

principle of , 125 
repairs through, 3, 5 

shop equipment, 39-43 

variety of applications of, 3 
Oxygen, cylinders, 27 

gas, result of too much, 35 

office of in combustion, 27 

table of different pressures of, 

at various temperatures, 29 



Preheating, aluminum, 117 

asbestos paper for oven, 55 

charcoal in, 53 

extraction and expansion in, 53 

drafts, protecting work from, in, 54 

fuels used in, 53 

in aluminum work, 116 

ovens, 56 

reasons for, 51 

setting up work, 56 

torch for, burning city gas, 54 

varied heats for different metals, 52 
Preheating agencies, 51-57 

fire-brick oven, 54 

ovens, 55, 56 

torch, burning city gas, 54 
Propeller shafts, welding automobile, 


Puddle method of welding aluminum, 
109, in 


Regulator, care of, 25 

construction and action of, 22, 23 

types of, 24 

Ring gears, building teeth on case- 
hardened, 96 
Retort cement, 42 

Sheet steel and iron, welding, 89 
Ships, repairs to seized German by 

acetylene process, 5 
Shop equipment, 39-43 
blacksmith forge, 42 

carbon rods and blocks, 43 

emery wheel, 41 

fire-brick table, 39 

flux container, 42 

retort cement, 42 
ventilation, 43 

Sparks, characteristic thrown off by 

emery wheel, 59 

Spring's, welding, futility of, 92, 93 
Steel, automobile frame, welding, 91 

automobile axles, welding of, 95 

automobile propeller shafts, 

welding, 95 

boiler flues, retipping, 98, 99 

boiler repairs, 99-101 

cast, procedure in welding, 88 

construction and expansion in 

welding, 87 

"corrugated" patch, 102, 103 

crank-shafts, welding of, 93, 94 

craters, formation of, in welding, 


definition, 81 

"dished" patch in boiler repairs, 


filler-rod used in welding, 82 

filler- rod to be used in welding, 97 

flame control in welding, 81, 82 

hard spots, formation of in weld- 

ing, 89 

heat treatment in welding un- 

equal sized pieces, 97 

internal strains in welding, 100 

" L " patches, 103 

metals, methods of distinguishing 

in welding, 87 

methods of welding, 82-86 

outside appearances in welding, 87 

overhead welding, 105 

sheet, welding, 89 

speed required in welding, 97 

springs, inadvisability of welding, 


susceptibility of when molten, 97 

teeth, building up of, 96 

vertical welding of, 104 

weld, broken, method of repair- 

ing, 96 

welding, difficulties of, 81, 92 
Steel welding, 81-105 



Table of different pressures of oxygen 
at various temperatures, 29 

Tanks inflammable gases, caution to 
be used in welding, 103 

Teeth, building up of, 96 

Temperature of acetylene gas flame, i 

Tip, size of in welding, 63 

Ventilation, 56, 108 

importance of in welding shop, 43 
Vertical welding, 104 

" V-ing " metal in welding, 63 


Welding, aluminum, 100-117 

brass, 106-108 

cast iron, procedure, 67-70 

malleable iron, 120-124 

Welding, methods of distinguishing 

between metals, 58 
sparks in determining kind of 

metals in, 58 
Welding of steel, 81-105 
broken weld, manner of re- 
pairing, 96 

cast, procedure in, 88 

contraction and expansion 

in, 87 

crank shafts, 93, 94 

craters, formation of in, 88 

filler-rod in, 91 

hard spots, formation of 

in, 89 
heat treatment in unequal 

sized pieces, 97 

methods of, 82-86 

overhead welding, 105 

springs, futility of weld- 
ing, 93 

teeth, building up of, .96 

vertical welding, 104 

Wiley Special Subject Catalogues 

For convenience a list of fhe Wiley Special Subject 
Catalogues, envelope size, has been printed. These 
are arranged in groups each catalogue having a key 
symbol. (See special Subject List Below). To 
obtain any of these catalogues, send a postal using 
the key symbols of the Catalogues desired. 

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Canning and Preserving. 

2 Architecture. Building. Masonry. 

3 Business Administration and Management. Law. 

Industrial Processes: Canning and Preserving; Oil and Gas 
Production; Paint; Printing; Sugar Manufacture; Textile. 

4a General; Analytical, Qualitative and Quantitative; Inorganic; 

4b Electro- and Physical; Food and Water; Industrial; Medical 

and Pharmaceutical; Sugar. 


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and Concrete; Excavation and Earthwork; Foundations; 

5c Railroads; Surveying. 

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gation Engineering; River and Harbor Engineering; Water 



5e Highways; Municipal Engineering; Sanitary Engineering; 
Water Supply. Forestry. Horticulture, Botany and 
Landscape Gardening. 

4> Design. Decoration. Drawing: General; Descriptive 
Geometry; Kinematics; Mechanical. 


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Distribution and Transmission; Dynamo-Electro Machinery; 
Electro-Chemistry and Metallurgy; Measuring Instruments 
and Miscellaneous Apparatus. 

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Naval Engineering. Military. Miscellaneous Books. 


<> General; Algebra; Analytic and Plane Geometry; Calculus; 
Trigonometry; Vector Analysis. 


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lOb Gas Power and Internal Combustion Engines; Heating and 

Ventilation; Refrigeration. 
lOc Machine Design and Mechanism; Power Transmission; Steam 

Power and Power Plants; Thermodynamics and Heat Power. 
11 Mechanics. 

12 Medicine. Pharmacy. Medical and Pharmaceutical Chem- 
istry. Sanitary Science and Engineering. Bacteriology and 


13 General; Assaying; Excavation, Earthwork, Tunneling, Etc.; 
Explosives; Geology; Metallurgy; Mineralogy; Prospecting; 




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